Toyota tundra – new features

13 TOYOTA TUNDRA – NEW FEATURES

NEW FEATURES

(cid:1)1UR-FE ENGINE

1. Description

12CEG01Y

12CEG02Y

The 1UR-FE engine is a 4.6-liter, 32-valve DOHC V8. This engine uses the Dual Variable Valve Timing-intelligent (Dual VVT-i) system, Direct Ignition System (DIS), Acoustic Control Induction System (ACIS), Electronic Throttle Control System-intelligent (ETCS-i), air injection system and Exhaust Gas Recirculation (EGR) control. These control functions achieve improved engine performance, fuel economy, and clean emissions.

(cid:2) Engine Specifications (cid:3)

14 TOYOTA TUNDRA – NEW FEATURES

No. of Cyls. & Arrangement 8-cylinder, V Type

Valve Mechanism 32-valve DOHC, Chain Drive (with Dual VVT-i)

Combustion Chamber Pentroof Type

Manifolds Cross-flow

Fuel System SFI

Ignition System DIS

cm3 (cu. in.)

mm (in.)

4608 (281.2) 94.0 × 83.0 (3.70 × 3.27) 10.2 : 1

Displacement Bore × Stroke Compression Ratio Max. Output (SAE-NET)*1 Max. Torque (SAE-NET)*1

Open Intake Closed Valve Timing Open Exhaust Closed

Firing Order 231 kW @ 5600 rpm (310 HP @ 5600 rpm) 443 N⋅m @ 3400 rpm (327 ft⋅lbf @ 3400 rpm) –18(cid:4) to 22(cid:4) BTDC 70(cid:4) to 30(cid:4) ABDC 62(cid:4) to 30(cid:4) BBDC – 8(cid:4) to 24(cid:4) ATDC 1 – 8 – 7 – 3 – 6 – 5 – 4 – 2

Octane Rating 87 or higher

Research Octane Number (RON) 91 or higher

Tailpipe Emission Regulation LEVII-ULEV, SFTP

LEVII, ORVR

Evaporative Emission Regulation Engine Service Mass*2 (Reference) kg (lb) 216.1 (476.5)

*1: Maximum output and torque ratings are determined by revised SAE J1349 standard. *2: The figure shown is the weight of the part without coolant and oil.

(cid:2) Valve Timing (cid:3)

15 TOYOTA TUNDRA – NEW FEATURES

: Intake valve opening angle : Exhaust valve opening angle

Exhaust VVT-i Operation Range Intake VVT-i Operation Range

TDC 8(cid:4) 18(cid:4) 22(cid:4) 24(cid:4)

70(cid:4)

62(cid:4)

30(cid:4) Exhaust VVT-i Operation Range 30(cid:4) Intake VVT-i Operation Range

12CEG03Y

(cid:2) Performance Curve (cid:3)

240

320

300

220

280

200

260

180

240

220

160

BDC

200

140

180

340 320 300 280 260 240

460 440 420 400 380 360 340 320

Torque N⋅m (ft⋅lbf)

120

160

140

100

120

100

1000

2000

3000

4000

5000

6000

Output (HP) kW

12CEG53Y

Engine Speed (rpm)

16 TOYOTA TUNDRA – NEW FEATURES

2. Features of 1UR-FE Engine

The 1UR-FE engine has achieved the following performance through the use of the items listed below:

(1) High performance and reliability

(2) Low noise and vibration

(3) Lightweight and compact design

(4) Good serviceability

(5) Clean emission and fuel economy

Item (2) (3) (4) (5) (cid:5)

(cid:5) (cid:5) (1) A taper squish shape is used for the combustion chamber. (cid:5) An aluminum alloy cylinder block containing an engine coolant distribution pathway is used.

(cid:5) (cid:5) Spiny-type liners are used in the cylinder bores. Engine Proper (cid:5) Cylinder block water jacket spacers are used. (cid:5) (cid:5) (cid:5) The piston skirt is coated with resin. (cid:5) (cid:5) (cid:5) A No. 1 oil pan made of aluminum alloy is used. (cid:5) (cid:5) Timing chains and chain tensioners are used. (cid:5) (cid:5) (cid:5) (cid:5) Hydraulic lash adjusters are used. Valve Mechanism (cid:5) (cid:5) Roller rocker arms are used. (cid:5) An oil filter with a replaceable element is used. (cid:5) Lubrication System A water-cooled type oil cooler is used.* (cid:5) A carbon filter is used in the air cleaner cap. (cid:5) (cid:5) A linkless-type throttle body is used. (cid:5) (cid:5) An intake manifold made of plastic is used. (cid:5) A step motor type EGR valve is used. (cid:5) Intake and Exhaust System A water-cooled type EGR cooler is used. (cid:5) (cid:5) (cid:5) Stainless steel exhaust manifolds are used.

(cid:5) Ceramic type Three-Way Catalytic converters (TWCs) are used.

(cid:5) (cid:5) Fuel System 12-hole type fuel injectors are used to improve the atomization of fuel.

(cid:5) (cid:5) (cid:5) The Direct Ignition System (DIS) makes ignition timing adjustment unnecessary. Ignition System (cid:5) (cid:5) (cid:5) Long-reach type iridium-tipped spark plugs are used.

(Continued)

*: Models with towing package

17 TOYOTA TUNDRA – NEW FEATURES

Item (1) (2) (3) (4) (5)

(cid:5) (cid:5) A segment conductor type generator is used. Charging System

(cid:5) Starting System A planetary reduction type starter is used.

(cid:5) (cid:5) A serpentine belt drive system is used. Serpentine Belt Drive System

(cid:5) (cid:5) A separator case is provided between the cylinder block and the intake manifold. Blowby Gas Ventilation System

(cid:5) An magnetic Resistance Element (MRE) type crankshaft position, a camshaft position, and VVT sensors are used.

(cid:5) (cid:5) The Electronic Throttle Control System-intelligent (ETCS-i) is used.

(cid:5) (cid:5)

Engine Control System (cid:5)

(cid:5) The Dual Variable Valve Timing-intelligent (Dual VVT-i) system is used. The Acoustic Control Induction System (ACIS) is used. (cid:5) The Exhaust Gas Recirculation (EGR) control is used. (cid:5) An air injection system is used. (cid:5) A starter control (cranking hold function) is used. (cid:5) An evaporative emission control system is used.

18 TOYOTA TUNDRA – NEW FEATURES

3. Engine Proper

Cylinder Head Cover

(cid:6) Lightweight yet high-strength aluminum cylinder head covers are used. (cid:6) An oil delivery pipe is installed inside the cylinder head covers. This ensures lubrication to the sliding parts of the valve rocker arms, improving reliability.

(cid:6) Large baffle plates are built into the cylinder head covers. As a result, the speed of blowby gas flow is reduced, and the oil mist is removed from the blowby gas. Due to this, the amount of oil lost is reduced.

Cylinder Head Cover LH Cylinder Head Cover RH Oil Delivery Pipe Baffle Plate Baffle Plate

12CEG04Y

Oil Delivery Pipe

Cylinder Head Cover Gasket LH Cylinder Head Cover Gasket RH

Cylinder Head Gasket

(cid:6) 3-layer steel-laminate type cylinder head gaskets are used. A shim is used around the cylinder bore of each gasket to help enhance sealing performance and durability. This results in improved fuel economy, reduced consumption rate of engine oil and reduced emission of exhaust gases.

(cid:6) The surface is coated with highly heat-resistant fluoro rubber to support high power output.

A A

Shim Right Bank Front

04E1EG07C

A – A Cross Section

Left Bank

19 TOYOTA TUNDRA – NEW FEATURES

Cylinder Head

(cid:6) The cylinder head structure has been simplified by separating the cam journal portion (camshaft housing) from the cylinder head.

(cid:6) The cylinder head, which is made of aluminum, contains a pentroof type combustion chamber. The spark plug is located in the center of the combustion chamber in order to improve the engine’s anti-knocking performance.

(cid:6) The port configuration is an efficient cross-flow type in which the intake ports face the inside of the V bank and the exhaust ports face the outside.

(cid:6) A siamese type intake port is used. The port diameter gradually decreases toward the combustion

chamber to optimize the airflow speed and intake pulsation. (cid:6) An air injection port is provided for the air injection system.

Camshaft Housing A Intake Side Intake Valve

Intake Side

Spark Plug Hole

04E1EG09C

080EG31TE

Exhaust Side Exhaust Side Exhaust Valve A

Bottom Side View A – A Cross Section

Air Injection Port

Front

04E1EG10C

Exhaust Side View

— REFERENCE —

036EG28TE

036EG29TE

Siamese Type Independent Type

20 TOYOTA TUNDRA – NEW FEATURES

Cylinder Block

1) General

(cid:6) The cylinder block is made of aluminum alloy. (cid:6) The cylinder block has a bank angle of 90(cid:4), a bank offset of 21 mm (0.827 in.) and a bore pitch of 105.5 mm (4.15 in.), resulting in a compact block in its length and width considering its displacement.

(cid:6) Spiny-type liners are used. (cid:6) An engine coolant distribution pathway is provided between the left and right banks. The engine coolant sent by the water pump passes through the engine coolant distribution pathway and flows to the cylinder head and water jackets of both banks. The engine coolant distribution pathway also cools the engine oil in the main oil hole located directly below the pathway.

(cid:6) A water passage is provided between the cylinder bores. By allowing the engine coolant to flow between the cylinder bores, this construction keeps the temperature of the cylinder walls uniform. (cid:6) Plastic cylinder block water jacket spacers are inserted in the water jacket. They control the flow of the engine coolant in order to attain a uniform temperature around the combustion chambers.

(cid:6) Installation bosses of the 4 knock sensors are located on the inner side of the left and right banks to enhance the accuracy of the knock sensors.

(cid:6) Air passage holes are provided on the bulkheads of the cylinder block. As a result, the air at the bottom of the cylinder flows smoother, and pumping loss (back pressure at the bottom of the piston generated by the piston’s reciprocating movement) is reduced to improve the engine’s output.

Water Passage 105.5 mm (4.15 in.) Knock Sensor Boss 21 mm (0.827 in.)

#2 #4 #8

#1 #3 #5 #7

Top Side View Engine Coolant Distribution Pathway

Air Passage Hole

90(cid:4)

12CEG05Y

Main Oil Hole

21 TOYOTA TUNDRA – NEW FEATURES

2) Spiny-type Liner

(cid:6) The liners are the spiny-type which have been manufactured so that their casting exteriors form large irregular surfaces in order to enhance the adhesion between the liners and the aluminum cylinder block. The enhanced adhesion helps heat dissipation, resulting in a lower overall temperature and heat deformation of the cylinder bores.

(cid:6) The shape of the cross-hatching of the liner surface has been optimized to improve oil retention performance, resulting in reduced friction.

Cylinder Block Cylinder Block Irregularly Shaped Outer Casting Surface of Liner

Enlarged View of Cross-hatching

12CEG06Y

Liner

A – A Cross Section

3) Cylinder Block Water Jacket Spacer

The temperature in the intake side of the cylinder bore tends to be lower. For this reason, a wide cylinder block water jacket spacer covers the cylinder bores in order to suppress the flow of the engine coolant and prevent excessive cooling. On the other hand, the temperature of the exhaust side of the cylinder bore tends to be higher. A cylinder block water jacket spacer covers the lower area of the cylinder bores in order to direct the engine coolant to the upper area of the cylinder bores where the temperature is higher. This makes the temperature around the cylinder bores more uniform. As a result, the viscosity of the engine oil (which lubricates the area between the wall surface of the cylinder bore and the piston) decreases, thus reducing friction between the cylinder bore and the piston.

Water Jacket Cylinder Block Water Jacket Spacer Intake Side

Exhaust Side

Cylinder Block Water Jacket Spacer

Front : Engine coolant flow : Engine coolant

12CEG07Y

Cross-sectional Image of Cylinder Bore

22 TOYOTA TUNDRA – NEW FEATURES

Piston

(cid:6) The pistons are made of aluminum alloy. (cid:6) A compact combustion chamber is provided on top of the piston to achieve stable combustion. Together with the pentroof type combustion chamber of the cylinder head, this achieves a high compression ratio, resulting in both high performance and excellent fuel economy.

(cid:6) A taper squish combustion chamber is used to improve anti-knocking performance and intake efficiency. In addition, engine performance and fuel economy are improved.

(cid:6) In order to reduce weight, cast holes are provided on the bottom of the piston head near the pin bosses as shown in the illustration below.

(cid:6) The piston skirt is coated with resin to reduce friction losses. (cid:6) A Physical Vapor Deposition (PVD) coating has been applied to the surface of the No. 1 compression ring and oil ring, in order to improve its wear resistance.

(cid:6) By increasing the machining precision of the cylinder bore diameter in the block, only one size of piston is required.

Resin Coating PVD Coating

Taper Squish Shape

No. 1 Compression Ring

Weight Reduction Area

No. 2 Compression Ring

12CEG17I

Oil Ring PVD Coating

Service Tip

The same pistons are used for both right and left banks. When installing a piston, the front mark should face the front of the engine.

23 TOYOTA TUNDRA – NEW FEATURES

Connecting Rod and Connecting Rod Bearing

(cid:6) Connecting rods that have been forged for high strength are used for weight reduction. (cid:6) Knock pins are used at the mating surfaces of the bearing caps of the connecting rod to minimize the shifting of the bearing caps during assembly.

(cid:6) Plastic region tightening bolts are used on the connecting rods. (cid:6) Resin-coated aluminum bearings are used for the connecting rod bearings. The connecting rod bearings are reduced in width to reduce friction.

12CEG11Y

Resin Coating Knock Pin Oil Jet

Plastic Region Tightening Bolt

Crankshaft

(cid:6) A crankshaft made of forged steel, which excels in rigidity and wear resistance, is used. (cid:6) The crankshaft has 5 main bearing journals and 6 balance weights.

Balance Weight Balance Weight

Engine Front

036EG02TE

No. 3 Journal No. 5 Journal No. 1 Journal No. 4 Journal No. 2 Journal

24 TOYOTA TUNDRA – NEW FEATURES

Crankshaft Bearing and Crankshaft Bearing Cap

(cid:6) The crankshaft bearings are made of aluminum alloy. (cid:6) The crankshaft bearings are reduced in width to reduce friction. The bearing lining surface is coated with resin to improve wear and seizure resistance.

(cid:6) The upper crankshaft bearing has an oil groove around its inside circumference. (cid:6) The crankshaft bearing caps use 4 plastic region tightening bolts of different sizes in the inner and outer sides to secure the journals. This makes the crankshaft bearing caps more compact and lightweight. In addition, each cap has been tightened laterally to improve its reliability.

Plastic Region Tightening Bolt

Upper Main Bearing

Oil Groove

Resin Coating

12CEG08Y

Crankshaft Bearing Cap Lower Main Bearing

Crankshaft Pulley

Torsional Damper Rubber

04E1EG18C

The crankshaft pulley uses torsional damper rubber and has been optimized to reduce noise and vibration.

25 TOYOTA TUNDRA – NEW FEATURES

Oil Pan

(cid:6) The No. 1 oil pan is made of aluminum alloy. (cid:6) The No. 1 oil pan is secured to the cylinder block and the transmission housing to increase rigidity. (cid:6) The shape of the oil pan baffle plate has been optimized to ensure the proper space between the crankshaft and the engine oil surface. This enhances the separation of oil flow and ventilation gases, thus reducing friction and improving lubrication performance.

Oil Pan Baffle Plate

No. 1 Oil Pan

080EG02TE

No. 2 Oil Pan

26 TOYOTA TUNDRA – NEW FEATURES

4. Valve Mechanism

General

(cid:6) Each cylinder of this engine has 2 intake valves and 2 exhaust valves. Intake and exhaust efficiency has been increased due to the larger total port areas.

(cid:6) This engine uses roller rocker arms with built-in needle bearings. This reduces the friction that occurs between the cams and the valve rocker arms that push the valves down, thus improving fuel economy. (cid:6) A hydraulic lash adjuster, which maintains a constant zero valve clearance through the use of oil pressure and spring force, is used.

(cid:6) To ensure highly accurate valve timing, separate primary timing chains are driven by the crankshaft in order to rotate the intake camshafts of the left and right banks. The exhaust camshafts are driven by the intake camshaft of the respective bank via secondary timing chains.

(cid:6) This engine has a Dual Variable Valve Timing-intelligent (Dual VVT-i) system which controls the intake and exhaust camshafts to provide optimal valve timing in accordance with driving conditions. Using this system, lower fuel consumption, higher engine performance, and lower exhaust emissions have been achieved. For details of Dual VVT-i control, see page 78.

Intake Camshaft Exhaust Camshaft

Valve Rocker Arm Secondary Timing Chain

Valve Spring Retainer

Hydraulic Lash Adjuster

Compression Spring

Valve Guide Bush

Valve Spring Seat

Valve

12CEG18Y

Secondary Timing Chain Primary Timing Chain

27 TOYOTA TUNDRA – NEW FEATURES

Camshaft

(cid:6) The camshafts are made of cast iron alloy. (cid:6) Oil passages are provided in the intake and exhaust camshafts in order to supply engine oil to the VVT-i system.

(cid:6) VVT-i controllers are installed on the front of the intake and exhaust camshafts to vary the timing of the intake and exhaust valves.

(cid:6) Together with the use of the roller rocker arms, the cam profile has been optimized. This results in increased valve lift when the valve begins to open and when it finishes closing, helping to achieve enhanced output performance.

Increased Valve Lift No. 2 Camshaft (Exhaust) No. 1 Camshaft (Intake) VVT-i Controller

No. 3 Camshaft (Intake)

Optimized Profile of Camshaft Lobe

Timing Rotor

VVT-i Controller

No. 4 Camshaft (Exhaust) Timing Rotor Oil Passage

VVT-i Controller

Cross Section of End of Intake Camshaft

080EG34S

Oil Passage

Cross Section of End of Exhaust Camshaft

28 TOYOTA TUNDRA – NEW FEATURES

Timing Chains and Chain Tensioners

(cid:6) Both the primary and secondary timing chains use roller chains with a pitch of 9.525 mm (0.375 in.). (cid:6) A chain tensioner is provided for each primary timing chain and secondary timing chain in each bank. (cid:6) Both the primary and secondary chain tensioners use oil pressure and a spring to maintain proper chain tension at all times. The tensioners suppress noise generated by the timing chains.

(cid:6) The chain tensioner for the primary timing chain is a ratchet type with a non-return mechanism. Furthermore, an oil pocket creates oil pressure when the engine is started, and simultaneously applies oil pressure to the chain tensioner. This prevents the timing chain from flapping and reduces noise.

Primary Chain Tensioner LH

Gasket

Oil Pocket Chain Tensioner (Primary) Secondary Chain Tensioner RH

Chain Damper RH Chain Slipper LH Secondary Chain Tensioner LH Main Spring Ball Secondary Timing Chain RH

Plunger Ball Spring

Secondary Timing Chain LH

Primary Chain Tensioner RH

Spring

Chain Damper LH Chain Slipper RH

Cam

080EG23S

Cam Spring Primary Timing Chain LH Primary Timing Chain RH

29 TOYOTA TUNDRA – NEW FEATURES

Timing Chain Cover

(cid:6) The timing chain cover has an integrated construction consisting of a cooling system (water pump and water passage) and a lubrication system (oil pump and oil passage). Thus, the number of parts has been reduced, resulting in a weight reduction.

(cid:6) A chain oil jet is provided in the oil pump cover to lubricate the timing chains.

Timing Chain Cover Water Pump Swirl Chamber

Water Pump Gasket

Oil Pump Cover Chain Oil Jet

Water Pump

12CEG12Y

Oil Pump Chamber Timing Chain Cover Oil Pump Rotor

Front Side View Back Side View

Hydraulic Lash Adjuster

(cid:6) The hydraulic lash adjuster, which is located at the fulcrum (pivot point) of the roller rocker arms, consists primarily of a plunger, a plunger spring, a check ball, and a check ball spring.

(cid:6) The engine oil supplied from the cylinder head and the built-in spring actuate the hydraulic lash adjuster. The oil pressure and the spring force, that act on the plunger, push the roller rocker arm against the cam, in order to adjust the clearance between the valve stem and rocker arm. This prevents the generation of noise during the opening and closing of the valves. As a result, engine noise has been reduced.

Cam Plunger Roller Rocker Arm Hydraulic Lash Adjuster

Oil Passage Oil Passage

Check Ball

04E1EG24C

Check Ball Spring

Plunger Spring

Service Tip

Valve clearance adjustment is not necessary because hydraulic lash adjusters are used on this model.

30 TOYOTA TUNDRA – NEW FEATURES

5. Lubrication System

General

(cid:6) The lubrication circuit is fully pressurized and oil passes through an oil filter. (cid:6) A cycloid rotor type oil pump is used. (cid:6) An oil filter with a replaceable element is used. (cid:6) A water-cooled type oil cooler is provided as optional equipment.

Oil Delivery Pipe (Cylinder Head Cover) Camshaft Timing Oil Control Valve

Oil Pump

Oil Filter Oil Strainer

12CEG19Y

Oil Cooler*

*: Models with towing package

(cid:2) Oil Circuit (cid:3)

31 TOYOTA TUNDRA – NEW FEATURES

Main Oil Hole

Crankshaft Journals

Cylinder Head RH Cylinder Head LH Cylinder Block Chain Oil Jet

Primary Chain Tensioner

Intake Camshaft Journals

Camshaft Timing OCV*2

Crankshaft Pins

VVT-i Controller

Oil Cooler*1

Exhaust Camshaft Journals

Connecting Rods

Oil Filter

Secondary Chain Tensioner

Hydraulic Lash Adjusters

Secondary Chain Tensioner

Hydraulic Lash Adjusters

Relief Valve

Oil Pump Oil Jets

04E1EG26C

Oil Pan

*1: Models with towing package *2: Oil Control Valve

32 TOYOTA TUNDRA – NEW FEATURES

Oil Pump

(cid:6) A compact cycloid rotor type oil pump, directly driven by the crankshaft, is used. (cid:6) This oil pump uses an internal relief method which circulates relief oil to the suction passage in the oil pump. This aims to minimize oil level change in the oil pan, reduce friction, and reduce the air mixing rate in the oil.

Timing Chain Cover

To Cylinder Block

Oil Pump Cover

Crankshaft

12DEG14I

Oil Pump Rotor (Cycloid Rotor) Oil Filter From Oil Strainer Relief Oil

Oil Jet

(cid:6) 4 oil jets for cooling and lubricating the pistons are provided in the cylinder block, in the center of the right and left banks.

(cid:6) These oil jets contain a check valve to prevent oil from being fed when the oil pressure is low. This prevents the overall oil pressure in the engine from dropping.

Oil Jet

Check Valve Oil

12CEG09Y

Oil Jet Cross Section

Cylinder Block

33 TOYOTA TUNDRA – NEW FEATURES

Oil Filter

(cid:6) A newly developed oil filter with a replaceable element is used. The oil filter element uses high-performance filter paper to improve filtration performance. It is also burnable for environmental protection.

(cid:6) A plastic oil filter cap is used for weight reduction. (cid:6) This oil filter has a structure which can drain the oil remaining in the oil filter. This prevents oil from spattering when the element is replaced and allows the technician to work without touching hot oil.

When Draining Oil

Oil Filter Element Oil Filter Bracket

Oil Filter Cap Oil Filter Element Drain Pipe

Oil Filter Drain Plug O-ring

Cross Section

Oil Filter Cap

12DEG15I

O-ring

Oil Filter Drain Plug

Service Tip

(cid:6) The oil in the oil filter can be drained by removing the oil filter drain plug and inserting the drain pipe supplied with the element into the oil filter. For details, refer to the 2010 TOYOTA TUNDRA Repair Manual. (cid:6) The engine oil maintenance interval for a model that has an oil filter with a replaceable element is the same as that for the conventional model.

34 TOYOTA TUNDRA – NEW FEATURES

Oil Cooler

(cid:6) To suppress the increase in oil temperature while towing and to improve reliability, a water-cooled oil cooler is used.

(cid:6) This oil cooler uses a square-shaped laminated aluminum core to achieve a lightweight, compact size, and high heat radiation.

Oil Filter Bracket

11YEG11Y

Oil Cooler : Engine coolant flow : Engine oil flow

35 TOYOTA TUNDRA – NEW FEATURES

6. Cooling System

General

(cid:6) The cooling system uses a pressurized forced circulation system with an open air type reservoir tank. (cid:6) An engine coolant distribution pathway is provided between the left and right banks of the cylinder block. (cid:6) A thermostat with a bypass valve is located on the plastic water inlet to maintain suitable temperature distribution in the cooling system.

(cid:6) An aluminum radiator core is used for weight reduction. (cid:6) A 2-stage temperature-controlled coupling fan is used. It rotates at lower speeds when the engine is cold to minimize fan noise.

(cid:6) Toyota Genuine Super Long Life Coolant (SLLC) is used as the engine coolant.

To Heater Radiator

Throttle Body Thermostat From Heater Radiator

Radiator

Water Pump

12CEG39Y

Oil Cooler*

*: Models with towing package

(cid:2) Water Circuit (cid:3)

36 TOYOTA TUNDRA – NEW FEATURES

EGR Valve Throttle Body Radiator Reservoir Tank Engine Coolant Distribution Pathway Transmission Oil Cooler (Warmer)

Thermostat Heater Radiator

Cylinder Head EGR Cooler

Oil Cooler*

Water Jacket

Cylinder Block Water Pump Cylinder Block Water Jacket Spacer Radiator

12CEG40I

(cid:2) Specifications (cid:3)

*: Models with towing package

non-amine, non-nitrite

Engine Coolant Type

Toyota Genuine Super Long Life Coolant (SLLC) or similar high quality ethylene glycol based and non-silicate, non-borate coolant with long-life hybrid organic acid technology (coolant with long-life hybrid organic acid technology is a combination of low phosphates and organic acids). Do not use plain water alone.

Color Pink

First Time 100000 miles (160000 km) Maintenance Intervals Subsequent

Thermostat Opening Temperature Every 50000 miles (80000 km) 80(cid:4)C to 84(cid:4)C (176(cid:4)F to 183(cid:4)F)

SLLC is pre-mixed (models for U.S.A. : 50% coolant and 50% deionized water, models for Canada: 55% coolant and 45% deionized water). Therefore, no dilution is needed when SLLC in the vehicle is added to or replaced.

37 TOYOTA TUNDRA – NEW FEATURES

Water Pump

(cid:6) A rust-resistant water pump rotor made of stainless steel is used. (cid:6) The water pump circulates the engine coolant to the engine coolant distribution pathway located between the left and right banks of the cylinder block.

Timing Chain Cover From Water Inlet Housing

Water Pump Gasket Rotor

Water Pump

12CEG14Y

Back Side View

Engine Coolant Distribution Pathway

The water pump circulates the engine coolant and directs it to the engine coolant distribution pathway located between the left and right banks. From there, the engine coolant is uniformly distributed to each cylinder of the cylinder block, and is also directly discharged to the cylinder heads. As a result, the cooling performance of the cylinder heads is assured and reliability is improved.

Heat Exchanger Cover

Engine Coolant Distribution Pathway From Water Pump

To Cylinder Head

Cylinder Block

12CEG10Y

Front Side

: Engine coolant flow

38 TOYOTA TUNDRA – NEW FEATURES

7. Intake and Exhaust System

General

(cid:6) A linkless-type throttle body is used, thus achieving excellent throttle control. (cid:6) The Electronic Throttle Control System-intelligent (ETCS-i) is used to ensure excellent throttle control in all operating ranges. For details, see page 73.

(cid:6) The Acoustic Control Induction System (ACIS) is used to improve engine performance in all speed

ranges. For details, see page 84. (cid:6) A plastic intake manifold is used. (cid:6) A step motor type EGR valve and a water-cooled EGR cooler are used in order to improve fuel economy. (cid:6) Stainless steel exhaust manifolds and exhaust pipes are used.

EGR Cooler Front Exhaust Pipe RH Tailpipe Intake Manifold

EGR Valve

Air Cleaner

Center Exhaust Pipe

Throttle Body Front Exhaust Pipe LH

12DEG01Y

Exhaust Manifold LH Exhaust Manifold RH

39 TOYOTA TUNDRA – NEW FEATURES

Air Cleaner

(cid:6) A nonwoven, fabric type air cleaner filter element is used. (cid:6) A carbon filter, which absorbs the HC that accumulates in the intake system when the engine is stopped, is used in the air cleaner case in order to reduce evaporative emissions. This filter is maintenance-free.

Air Cleaner Cap

Carbon Filter

Air Cleaner Filter Element (Nonwoven Fabric)

04E0EG49C

Air Cleaner Case

Throttle Body

(cid:6) A linkless-type throttle body, in which the throttle position sensor and the throttle control motor are integrated, is used. It achieves excellent throttle valve control.

(cid:6) For the throttle control motor, a DC motor with excellent response and minimal power consumption is used. The ECM performs duty cycle control of the direction and the amperage of the current supplied to the throttle control motor in order to regulate the throttle valve angle.

Throttle Valve

12CEG51Y

Throttle Position Sensor Portion

Throttle Control Motor

40 TOYOTA TUNDRA – NEW FEATURES

Intake Manifold

(cid:6) An intake manifold with a built-in plastic intake air chamber is used for weight reduction. (cid:6) The diameter and length of the port have been optimized to achieve high torque in all driving ranges. (cid:6) The intake manifold contains valves for the Acoustic Control Induction System (ACIS), and the actuator is laser-welded to the intake manifold.

Left Bank Passage

Right Bank Passage Front ACIS Actuator

Front Intake Air Control Valve

12DEG02Y

Laser-welding

— REFERENCE —

Laser-welding:

In laser-welding, a laser-absorbing material (for the intake manifold) is joined to a laser-transmitting material (for the ACIS actuator). Laser beams are then irradiated from the laser-transmitting side. The beams penetrate the laser-transmitting material to heat and melt the surface of the laser-absorbing material. Then, the heat of the laser-absorbing material melts the laser-transmitting material and causes both materials to become welded.

41 TOYOTA TUNDRA – NEW FEATURES

EGR Valve

(cid:6) A step motor is used on the EGR valve to enable the ECM to directly control the EGR valve. (cid:6) The water circulates through the EGR valve to ensure proper cooling performance.

Exhaust Gas Out (To Intake Manifold)

Engine Coolant In

Engine Coolant Out

Exhaust Gas In (From EGR Cooler)

12CEG20Y

EGR Valve Cross Section

EGR Cooler

(cid:6) The water-cooled type EGR cooler is used in the EGR passage between the cylinder head and EGR valve. (cid:6) In the water-cooled type EGR cooler, engine coolant flows to the 4-layered gas passage to cool down.

Exhaust Gas Out Exhaust Gas Out

Exhaust Gas In Engine Coolant Out

A Engine Coolant Out A

Exhaust Gas In Engine Coolant In

Engine Coolant

Exhaust Gas

12CEG21Y

EGR Cooler A – A Cross Section Engine Coolant In

42 TOYOTA TUNDRA – NEW FEATURES

Exhaust Manifold

(cid:6) A stainless steel exhaust manifold is used for weight reduction and rust resistance. (cid:6) The exhaust manifold for each bank uses a single structure (in a 4-1 grouping). (cid:6) The exhaust manifold heat insulator is made of corrugated aluminum. This ensures rigidity, and at the same time, increases the surface area to improve heat dissipation. Furthermore, a floating construction is used in the tightened area to reduce the transfer of heat and vibration to the heat insulator and to improve reliability.

(cid:6) Along with the use of the air injection system, air injection pipes are provided for the right and left bank exhaust manifolds.

Floating Construction

Heat Insulator Tightened Area Cross Section Air Injection Pipe Air Injection Pipe

Heat Insulator RH Exhaust Manifold LH

Heat Insulator LH

Exhaust Manifold RH

Corrugated

12DEG03Y

Heat Insulator Cross Section

43 TOYOTA TUNDRA – NEW FEATURES

Exhaust Pipe

(cid:6) The exhaust pipes are made of stainless steel to reduce their weight and improve rust resistance. (cid:6) 2 ceramic type Three-Way Catalytic converters (TWCs) are provided in the front exhaust pipe for the right bank, and another 2 are also provided for the left bank. As a result, the exhaust emission performance of the engine is improved.

Tailpipe

Main Muffler Front Exhaust Pipe RH

TWC

Sub Muffler

Center Exhaust Pipe

11AEG01Y

Front Exhaust Pipe LH TWC

44 TOYOTA TUNDRA – NEW FEATURES

8. Fuel System

General

(cid:6) A fuel cut control is used to stop the fuel pump when SRS airbags deploy in a frontal or side collision. For details, see page 87.

(cid:6) Compact 12-hole type fuel injectors are used to improve the atomization of fuel. (cid:6) Quick connectors are used to connect the fuel lines for ease of serviceability. (cid:6) A multi-layer plastic fuel tank is used. (cid:6) An evaporative emission control system is used. For details, see page 95.

Fuel Tank Canister Fuel Delivery Pipe

Fuel Pressure Regulator

Fuel Pump Assembly (cid:6) Fuel Pump (cid:6) Fuel Filter (cid:6) Fuel Sender Gauge Fuel Injector

12DEG04Y

Quick Connector

Pulsation Damper

45 TOYOTA TUNDRA – NEW FEATURES

Fuel Injector

A 12-hole fuel injector with optimized fuel flow amount is used to improve the atomization of fuel.

Bottom Side View

10ZEG11Y

Fuel Injector Cross Section

Delivery Pipe

(cid:6) Fuel delivery pipes formed from stamped steel are used to deliver fuel to the fuel injectors. (cid:6) A pulsation damper is provided on the fuel delivery pipe in the left bank. A fuel pressure regulator is installed on the right bank fuel delivery pipe.

Fuel Pressure Regulator

12DEG05Y

Fuel Delivery Pipe Pulsation Damper

46 TOYOTA TUNDRA – NEW FEATURES

9. Ignition System

General

(cid:6) A Direct Ignition System (DIS) is used. The DIS improves ignition timing accuracy, reduces high-voltage loss, and enhances the overall reliability of the ignition system by eliminating the distributor.

(cid:6) The DIS is an independent ignition system which has one ignition coil (with an integrated igniter) for each cylinder.

+B Ignition Coil (with Igniter) Spark Plug

IGT1 No. 1 Cylinder

IGT2 G2 No. 2 Cylinder

Camshaft Position Sensor IGT3 No. 3 Cylinder

IGT4 No. 4 Cylinder

Crankshaft Position Sensor

NE ECM IGT5 No. 5 Cylinder

IGT6 No. 6 Cylinder

IGT7 No. 7 Cylinder

Various Sensors No. 8 Cylinder

036EG22TE

IGT8 IGF1 IGF2

Ignition Coil

Igniter

Primary Coil The DIS provides 8 ignition coils, one for each cylinder. The spark plug caps, which provide contact to spark plugs, are integrated with the ignition coil. Also, an igniter is enclosed to simplify the system.

Iron Core

Secondary Coil

Spark Plug Cap

05AEG39TE

Ignition Coil Cross Section

47 TOYOTA TUNDRA – NEW FEATURES

Spark Plug

(cid:6) Long-reach type spark plugs are used. This type of spark plug allows the area of the cylinder head that receives the spark plugs to be made thick. Thus, the water jacket can be extended near the combustion chamber, contributing to cooling system performance.

(cid:6) Iridium-tipped spark plugs are used to achieve 120000 mile (200000 km) maintenance intervals. By using an iridium center electrode, ignition performance superior to that of platinum-tipped spark plugs has been achieved and durability has been increased.

11YEG12Y

Iridium Tip Long-reach Platinum Tip

Water Jacket Water Jacket

11YEG13Y

(cid:2) Specifications (cid:3)

Cylinder Head Cross Section

Manufacturer DENSO

Type SK20HR11

Plug Gap 1.0 to 1.1 mm (0.0394 in. to 0.043 in.)

48 TOYOTA TUNDRA – NEW FEATURES

10. Charging System

General

(cid:6) A compact and lightweight segment conductor type generator that generates high amperage output in a highly efficient manner is provided as standard equipment.

(cid:6) This generator has a joined segment conductor system in which multiple segment conductors are welded together to form the stator. Compared to the conventional winding system, the electrical resistance is lower due to the shape of the segment conductors, and their arrangement helps to make the generator compact.

Stator Stator Stator Conductor Wire Stator Segment Conductor Segment Conductor Conductor Wire

A B Joined

206EG40

206EG41

A – A Cross Section B – B Cross Section A Joined Segment Conductor System Winding System B

Conventional Type Generator Segment Conductor Type Generator

Stator

Segment Conductor

Cross Section

206EG42

Stator of Segment Conductor Type Generator

(cid:2) Generator Provision (cid:3)

49 TOYOTA TUNDRA – NEW FEATURES

Generator Type Vehicle Type SC1 SE0 (cid:5) Regular Cab — (cid:5) SR5 — (cid:5) Standard Deck Limited — Double Cab

Long Deck — (cid:5) SR5 CrewMax — (cid:1)*2 (cid:5) Limited — SC2 (cid:1)*1 (cid:1)*1 (cid:1)*1 (cid:5) (cid:1)*1 (cid:1)*1

(cid:2) Specifications (cid:3)

(cid:5): Standard equipment (cid:1): Optional equipment —: Not equipped *1: Models with towing package *2: Models with rear seat entertainment system (except models with towing package)

Type SE0 SC1 (cid:2) SC2 (cid:2) Rated Voltage 12 V

(cid:2) Wiring Diagram (cid:3)

Rated Output 100 A 130 A (cid:2) 150 A (cid:2) Initial Output Starting Speed Max. 1500 rpm

Generator

IG Ignition Switch

Regulator

L Discharge Warning Light

12DEG18I

SE0 type

50 TOYOTA TUNDRA – NEW FEATURES

Generator

Ignition Switch

S Regulator

L Discharge Warning Light

11AEG07Y

SC1 and SC2 type

Dual Winding System (SC1 or SC2 Type Generator)

A dual winding system is used. This system consists of 2 sets of 3-phase windings whose phases are staggered by 30(cid:4). This system results in the reduction of both electrical noises (ripple and spike) and magnetic noise (a hum heard as generator load is increased). This system significantly suppresses noise at the source (generator). Since the waves that the respective windings generate have opposite polarities, magnetic noise is reduced. However, the electrical power generated does not cancel itself out due to the use of separate rectifiers. The opposite polarities generated are shown below:

30(cid:4)

A C B

3-phase Winding 2 Sets of 3-phase Windings

Voltage Staggered 30(cid:4) Voltage C

Rotational Angle Rotational Angle

A B

279EG32

Dual Winding Single Winding

51 TOYOTA TUNDRA – NEW FEATURES

11. Starting System

(cid:2) Specification (cid:3)

A planetary reduction type starter is used.

Models Standard Cold Area Specification

Type PA70 PA78S

Rated Output 1.6 kW 2.0 kW (cid:2) 12 V

Rated Voltage Length*1 136.1 mm (5.36 in.) 168.9 mm (6.65 in.)

Weight 4300 g (9.48 lb) (cid:2) Rotating Direction 3150 (6.95 lb) Clockwise*2

*1: Length from the mounted area to the rear end of the starter *2: Viewed from pinion side

12. Serpentine Belt Drive System

(cid:6) A serpentine belt drive system, which drives all accessory components by a single V-ribbed belt, is used.

It reduces the overall engine length, weight and the number of engine parts. (cid:6) An automatic tensioner is used. This makes tension adjustment unnecessary.

Water Pump Pulley

Fan Pulley

V-ribbed Belt Tensioner (Automatic Tensioner)

Idler Pulley

*1 Vane Pump Pulley (Power Steering)

Air Conditioning Compressor Pulley*2 Generator Pulley

12DEG17I

Crankshaft Pulley

*1: Models without air conditioning *2: Models with air conditioning

52 TOYOTA TUNDRA – NEW FEATURES

13. Blow−by Gas Ventilation System

General

(cid:6) The oil separator portion of the cylinder head covers has been made compact through the use of an independent separator case. This contributes to making the entire engine compact.

(cid:6) Fresh air is drawn from the right and left bank cylinder head covers to improve the ventilation inside the engine and improve the deterioration resistance of the engine oil.

Throttle Valve

Intake Manifold

PCV Valve

Oil Separator Portion Oil Separator Portion

Separator Case

Cylinder Head Cover RH Cylinder Head Cover LH

04E1EG45C

: Blowby gas : Fresh air

53 TOYOTA TUNDRA – NEW FEATURES

Separator Case

(cid:6) A plastic separator case is provided between the cylinder block and the intake manifold in order to separate the engine oil included in the blowby gas.

(cid:6) An inertial impaction system is used in the construction for separating the engine oil in the separator case. Blowby gas containing engine oil hits the plate, thus causing the engine oil to adhere and accumulate on the plate. Then, the oil drips down by way of gravity. Thus, this system efficiently separates the engine oil from the blowby gas. This improves the rate of the collection of the engine oil and reduces the amount of engine oil consumption.

Intake Manifold

Separator Case

Cylinder Block

To Intake Manifold Plate PCV Valve PCV Valve Separator Case

Blowby Gas : Blowby gas containing engine oil From Cylinder Block : Blowby gas Engine Oil : Engine oil

To Oil Pan

12DEG06I

Cross-sectional Image of Separator Case

54 TOYOTA TUNDRA – NEW FEATURES

14. ENGINE CONTROL SYSTEM

General

The engine control system of the 1UR-FE engine has the following features:

System

Outline (cid:6) An L-type SFI system directly detects the intake air mass using a hot-wire type air flow meter.

(cid:6) An independent injection system (in which fuel is injected once into each intake port for each 2 revolutions of the crankshaft) is used. (cid:6) Fuel injection takes 2 forms: – Synchronous injection, in which injection always occurs at the same timing relative to the firing order. Sequential Multiport Fuel Injection (SFI) – Non-synchronous injection, in which injection is effected regardless of the crankshaft angle. (cid:6) Synchronous injection is further divided into 2 sub-categories:

– Group injection, conducted during a cold start. – Independent injection, conducted after the engine has started. (cid:6) Ignition timing is determined by the ECM based on signals from various sensors. The ECM corrects ignition timing in response to engine knocking. Electronic Spark Advance (ESA)

(cid:6) This system selects the optimal ignition timing in accordance with the signals received from the sensors and sends the (IGT) ignition signal to the igniter.

Electronic Throttle Control System-intelligent (ETCS-i) [See page 73] Optimally controls the throttle valve opening in accordance with the amount of accelerator pedal effort and the condition of the engine and the vehicle.

Controls the intake and exhaust camshafts to optimal valve timing in accordance with the engine operating conditions. Dual Variable Valve Timing-intelligent (Dual VVT-i) [See page 78]

Acoustic Control Induction System (ACIS) [See page 84] The intake air passages are switched based on engine speed and throttle valve opening angle to provide high performance in all engine speed ranges.

EGR Control [See page 86]

Based on the signals received from the various sensors, the ECM determines the EGR volume via EGR valve in accordance with the engine condition. (cid:6) Based on signals from the ECM, the fuel pump ECU controls the fuel pump in 3 stages. Fuel Pump Control [See page 87] (cid:6) The fuel pump is stopped when the SRS airbag is deployed in a frontal, side, or side rear collision.

Air Injection Control [See page 89] The ECM controls the air injection time based on the signals from the crankshaft position sensor, engine coolant temperature sensor, mass air flow meter and air pressure sensor.

Starter Control (Cranking Hold Function) [See page 93] Once the ignition switch is turned ON while the brake pedal is depressed, this control continues to operate the starter until the engine has started.

(Continued)

55 TOYOTA TUNDRA – NEW FEATURES

System Outline

Air-fuel Ratio Sensor and Heated Oxygen Sensor Heater Control Maintains the temperature of the air-fuel ratio sensors or heated oxygen sensors at an appropriate level to increase the detection accuracy of the exhaust gas oxygen concentration.

Air Conditioning Cut-off Control*

By turning the air conditioning compressor on or off in accordance with the engine condition, driveability is maintained. (cid:6) The ECM controls the purge flow of evaporative emission (HC) in the canister in accordance with the engine conditions.

Evaporative Emission Control [See page 95]

(cid:6) Approximately five hours after the ignition switch has been turned off, the ECM operates the pump module to detect any evaporative emission leakage occurring between the fuel tank and the canister through changes in the fuel tank pressure.

Engine Immobiliser Prohibits fuel delivery and ignition if an attempt is made to start the engine with an invalid key.

Diagnosis [See page 107] When the ECM detects a malfunction, the ECM records the malfunction and memorizes information related to the fault.

Fail-safe [See page 107] When the ECM detects a malfunction, the ECM stops or controls the engine in accordance with the data already stored in the memory.

*: Models with air conditioning

56 TOYOTA TUNDRA – NEW FEATURES

Construction

The configuration of the engine control system is as shown in the following chart:

SENSORS ACTUATORS

SFI MASS AIR FLOW METER

No. 1 FUEL INJECTOR

No. 2 FUEL INJECTOR INTAKE AIR TEMPERATURE SENSOR

No. 3 FUEL INJECTOR

No. 4 FUEL INJECTOR CRANKSHAFT POSITION SENSOR No. 5 FUEL INJECTOR

No. 6 FUEL INJECTOR

CAMSHAFT POSITION SENSOR No. 7 FUEL INJECTOR

No. 8 FUEL INJECTOR

ENGINE COOLANT TEMPERATURE SENSOR

ESA

IGNITION COIL (with IGNITER)

No. 1, 4, 6, 7

ACCELERATOR PEDAL POSITION SENSOR

IGNITION COIL (with IGNITER)

No. 2, 3, 5, 8

THROTTLE POSITION SENSOR ECM

SPARK PLUGS SPARK PLUGS

KNOCK SENSORS

Bank 1, Sensor 1

No. 1, 4, 6, 7

No. 2, 3, 5, 8

Bank 1, Sensor 2

Bank 2, Sensor 1

Bank 2, Sensor 2

ETCS-i

THROTTLE CONTROL MOTOR

VVT SENSORS (INTAKE)

VVT SENSORS (EXHAUST)

VVT-i (INTAKE)

STOP LIGHT SWITCH

CAMSHAFT TIMING OIL CONTROL VALVE (Bank 1) IGNITION SWITCH

12DEG12I

CAMSHAFT TIMING OIL CONTROL VALVE (Bank 2) VACUUM SENSOR

(Continued)

57 TOYOTA TUNDRA – NEW FEATURES

VVT-i (EXHAUST) TRANSFER NEUTRAL POSITION SWITCH*1

CAMSHAFT TIMING OIL CONTROL VALVE (Bank 1) 4WD CONTROL ECU*1

CAMSHAFT TIMING OIL CONTROL VALVE (Bank 2) AIR PRESSURE SENSOR (Bank 1)

ACIS AIR PRESSURE SENSOR (Bank 2)

VSV

GENERATOR

FUEL PUMP CONTROL POWER STEERING OIL PRESSURE SENSOR CIRCUIT OPENING RELAY

AIR CONDITIONING AMPLIFIER*2 FUEL PUMP ECU

PARK/NEUTRAL POSITION SWITCH FUEL PUMP

ECM (cid:6) Neutral Start Signal (cid:6) Shift Lever Position Signal

TRANSMISSION CONTROL SWITCH

AIR INJECTION CONTROL

AIR INJECTION CONTROL DRIVER (Bank 1) CANISTER PUMP MODULE

AIR SWITCHING VALVE (Bank 1) CANISTER PRESSURE SENSOR

AIR PUMP (Bank 1) AIR-FUEL RATIO SENSORS

(Bank 1, Sensor 1)

HEATED OXYGEN SENSORS

(Bank 2, Sensor 1) AIR INJECTION CONTROL DRIVER (Bank 2)

AIR SWITCHING VALVE (Bank 2) (Bank 1, Sensor 2)

08LEG01Y

(Bank 2, Sensor 2) AIR PUMP (Bank 2)

(Continued) *1: 4WD models *2: Models with air conditioning

58 TOYOTA TUNDRA – NEW FEATURES

CRUISE CONTROL MAIN SWITCH*1 STARTER CONTROL

ACC CUT RELAY

TOW/HAUL PATTERN SELECT SWITCH*2 STARTER RELAY

STARTER SIGNAL

IMMOBILISER CODE ECU

EGR CONTROL

COMBINATION METER EGR VALVE

MIL

ECM (cid:6) Vehicle Speed Signal

AIR-FUEL RATIO SENSOR HEATER

AIR-FUEL RATIO SENSOR & HEATED OXYGEN SENSOR HEATER CONTROL

EFI MAIN RELAY

(Bank 1, Sensor 1)

HEATED OXYGEN SENSOR HEATER

(Bank 2, Sensor 1) DEFOGGER RELAY

(Bank 1, Sensor 2)

BATTERY (Bank 2, Sensor 2)

DLC3 EVAPORATIVE EMISSION CONTROL

CANISTER PUMP MODULE

LEAK DETECTION PUMP CENTER AIRBAG SENSOR ASSEMBLY VENT VALVE

12DEG13I

PURGE VSV SKID CONTROL ECU CAN*3

*1: Models with cruise control system *2: Models with towing package *3: V bus

59 TOYOTA TUNDRA – NEW FEATURES

Vent Valve

Fuel Pump ECU

Mass Air Flow Meter

Canister Pump Module

Intake Air Temperature Sensor

Canister

Fuel Pump

Canister Pressure Sensor

Purge VSV

Accelerator Pedal Position Sensor

Throttle Position Sensor

Throttle Control Motor

Air Switching Valve (Bank 1)

Air Pressure Sensor (Bank 2)

Air Pressure Sensor (Bank 1)

EGR Valve

Air Injection Control Driver (Bank 2)

Air Injection Control Driver (Bank 1)

VSV (for ACIS)

Air Pump (Bank 2)

Air Pump (Bank 1)

Air Switching Valve (Bank 2)

EGR Cooler

Fuel Injector

VVT Sensor (Bank 1, Intake)

Vacuum Sensor

Camshaft Position Sensor

VVT Sensor (Bank 2, Intake)

VVT Sensor (Bank 1, Exhaust)

VVT Sensor (Bank 2, Exhaust)

Ignition Coil (with Igniter)

Engine Coolant Temp. Sensor

Air-fuel Ratio Sensor (Bank 2, Sensor 1)

Air-fuel Ratio Sensor (Bank 1, Sensor 1)

Heated Oxygen Sensor (Bank 2, Sensor 2)

Knock Sensor 1, 2 (Bank 1)

Knock Sensor 1, 2 (Bank 2)

Heated Oxygen Sensor (Bank 1, Sensor 2)

Crankshaft Position Sensor

ECM

Air Conditioning Amplifier

Circuit Opening Relay

DLC3

CAN (V Bus)

Combination Meter (cid:6) Vehicle Speed Signal (cid:6) MIL

12CEG35I

*2: Intake camshaft timing oil control valve (Bank 2)

*1: Intake camshaft timing oil control valve (Bank 1) *3: Exhaust camshaft timing oil control valve (Bank 1) *4: Exhaust camshaft timing oil control valve (Bank 2)

Engine Control System Diagram

60 TOYOTA TUNDRA – NEW FEATURES

Layout of Main Components

Heated Oxygen Sensor (Bank 2, Sensor 2)

Canister Pump Module (cid:6) Leak Detection Pump (cid:6) Pressure Sensor (cid:6) Vent Valve Air-fuel Ratio Sensor (Bank 2, Sensor 1) Canister

Mass Air Flow Meter (cid:6) Intake Air Temperature Sensor

Fuel Pump ECU

12DEG07I

Fuel Pump Assembly

Throttle Body (cid:6) Throttle Position Sensor (cid:6) Throttle Control Motor Heated Oxygen Sensor (Bank 1, Sensor 2)

Air-fuel Ratio Sensor (Bank 1, Sensor 1)

MIL

DLC3

11AEG10Y

Accelerator Pedal Position Sensor

61 TOYOTA TUNDRA – NEW FEATURES

Air Switching Valve (Bank 2) (cid:6) Air Pressure Sensor Air Switching Valve (Bank 1) (cid:6) Air Pressure Sensor

ECM

Air Pump (Bank 2)

Air Injection Control Driver

12DEG08Y

Air Pump (Bank 1)

EGR Valve Camshaft Position Sensor VVT Sensor (Bank 2, Intake) VSV (for ACIS) Vacuum Sensor Purge VSV ACIS Actuator

Camshaft Timing Oil Control Valve (Bank 2, Intake)

VVT Sensor (Bank 1, Intake)

Camshaft Timing Oil Control Valve (Bank 2, Exhaust) VVT Sensor (Bank 1, Exhaust)

Engine Coolant Temperature Sensor Camshaft Timing Oil Control Valve (Bank 1, Exhaust) VVT Sensor (Bank 2, Exhaust)

Crankshaft Position Sensor Camshaft Timing Oil Control Valve (Bank 1, Intake)

Fuel Injector Fuel Injector Knock Sensor 2 (Bank 1) Knock Sensor 2 (Bank 2)

Ignition Coil (with Igniter) Ignition Coil (with Igniter)

12DEG09Y

Fuel Injector Fuel Injector

Knock Sensor 1 (Bank 1) Knock Sensor 1 (Bank 2)

62 TOYOTA TUNDRA – NEW FEATURES

Main Component of Engine Control System

1) General

The main components of the 1UR-FE engine control system are as follows:

Components Outline Quantity

ECM 32-bit CPU 1

Hot-wire Type 1 Mass Air Flow Meter

Thermistor Type 1

1 Function The ECM optimally controls the SFI, ESA and ISC to suit the operating conditions of the engine in accordance with the signals provided by the sensors. This sensor has a built-in hot-wire to directly detect the intake air mass and flow rate. This sensor detects the intake air temperature by means of an internal thermistor. This sensor detects the amount of pedal effort applied to the accelerator pedal. This sensor detects the throttle valve opening angle. This sensor detects the engine speed and the crankshaft position. This sensor detects the camshaft position and performs the cylinder identification.

This sensor detects the actual valve timing.

This sensor detects the actual valve timing. Intake Air Temperature Sensor Accelerator Pedal Position Sensor Throttle Position Sensor Crankshaft Position Sensor Camshaft Position Sensor VVT Sensor (Intake) VVT Sensor (Exhaust) 1 each bank 1 each bank

indirectly from Knock Sensor 2 each bank Hall IC Type (Non-contact Type) Hall IC Type (Non-contact Type) MRE Type (Rotor Teeth/36-2) MRE Type (Rotor Teeth/3) MRE Type (Rotor Teeth/3) MRE Type (Rotor Teeth/3) Built-in Piezoelectric Element (Flat Type)

the sensor

Heated Oxygen Sensor Cup Type with Heater 1 each bank electromotive

Air-fuel Ratio Sensor Planar Type with Heater 1 each bank

Vacuum Sensor 1 Semiconductor Silicon Chip Type

Thermistor Type 1 Engine Coolant Temperature Sensor

contains fuel Fuel Injector 12-hole Type 8

Camshaft Timing Oil Control Valve Electromagnetic Coil Type 2 each bank

This sensor detects an occurrence of the engine knocking the vibration of the cylinder block caused by the occurrence of engine knocking. oxygen detects This concentration in the exhaust emission by measuring force the generated in the sensor itself. As with the heated oxygen sensor, this sensor detects the oxygen concentration in the exhaust emissions. However, it detects the oxygen concentration in the exhaust emissions linearly. This sensor uses built-in semiconductors to detect the intake manifold pressure. This sensor detects the engine coolant temperature by means of an internal thermistor. This an injector electromagnetically operated nozzle to inject fuel into the intake port. The camshaft timing oil control valve changes the valve timing by switching the oil passage that acts on the VVT-i controller in accordance with the signals received from the ECM.

63 TOYOTA TUNDRA – NEW FEATURES

2) Mass Air Flow Meter

(cid:6) This mass air flow meter, which is a slot-in type, allows a portion of the intake air to flow through the detection area. By directly measuring the mass and the flow rate of the intake air, the detection precision is improved and the intake air resistance is reduced.

(cid:6) This mass air flow meter has a built-in intake air temperature sensor.

Air Flow

273GX15

Intake Air Temperature Sensor

3) Knock Sensor (Flat Type)

a. General

In the conventional type knock sensor (resonant type), a vibration plate which has the same resonance point as the knocking frequency of the engine is built in and can detect the vibration in this frequency band. However, a flat type knock sensor (non-resonant type) has the ability to detect vibration in a wider frequency band from approximately 6 kHz to 15 kHz, and has the following feature:

(cid:6) The engine knocking frequency will change a little depending on the engine speed. The flat type knock sensor can detect the vibration even when the engine knocking frequency is changed. Thus the vibration detection ability has been increased compared to the conventional type knock sensor, and more precise ignition timing control has been made possible.

: Resonance characteristic of conventional type

: Resonance characteristic of flat type

(V) A A: Detection band of conventional type

B: Detection band of Voltage flat type

214CE04

Frequency (Hz)

Characteristic of Knock Sensor

64 TOYOTA TUNDRA – NEW FEATURES

b. Construction

(cid:6) The flat type knock sensor is installed on the engine through the stud bolt installed on the cylinder block. For this reason, a hole for the stud bolt runs through the center of the sensor.

(cid:6) Inside of the sensor, a steel weight is located on the upper portion and a piezoelectric element is located under the weight through the insulator.

(cid:6) The open/short circuit detection resistor is integrated.

Open/Short Circuit Detection Resistor Steel Weight

Piezoelectric Element Insulator

Vibration Plate Piezoelectric Element

214CE01

214CE02

Flat Type Knock Sensor (Non-resonant Type) Conventional Type Knock Sensor (Resonant Type)

c. Operation

Steel Weight

The knocking vibration is transmitted to the steel weight and its inertia applies pressure to the piezoelectric element. This action generates electromotive force. Inertia

214CE08

Piezoelectric Element

d. Open/Short Circuit Detection Resistor

(cid:6) While the ignition is ON, the open/short circuit detection resistor in the knock sensor and the resistor in the ECM keep the voltage at terminal KNK1 of the engine constant.

(cid:6) An Integrated Circuit (IC) in the ECM constantly monitors the voltage of terminal KNK1. If the open/short circuit occurs between the knock sensor and the ECM, the voltage of terminal KNK1 will change and the ECM will detect the open/short circuit and store a Diagnostic Trouble Code (DTC).

ECM

Piezoelectric Element 5 V

Flat Type Knock Sensor 220 kΩ KNK1

IC 200 kΩ EKNK

214CE06

Open/Short Circuit Detection Resistor

65 TOYOTA TUNDRA – NEW FEATURES

Service Tip

These knock sensors are mounted in specific directions at specific angles. To prevent the right and left bank wiring connectors from being interchanged, be sure to install each sensor in its prescribed direction. For details, refer to the 2010 TOYOTA TUNDRA Repair Manual.

4) Vacuum Sensor

The vacuum sensor consists of a silicon chip that changes its electrical resistance when pressure is applied to it. The sensor converts the pressure into an electrical signal, and sends it to the ECM in an amplified form.

12CEG42Y

Silicon Chip

66 TOYOTA TUNDRA – NEW FEATURES

5) Air-fuel Ratio Sensor and Heated Oxygen Sensor

a. General

(cid:6) The heated oxygen sensor and the air-fuel ratio sensor differ in output characteristics. (cid:6) The output voltage of the heated oxygen sensor changes in accordance with the oxygen concentration in the exhaust gas. The ECM uses this output voltage to determine whether the present air-fuel ratio is richer or leaner than the stoichiometric air-fuel ratio.

(cid:6) Approximately 0.4 V is constantly applied to the air-fuel ratio sensor, which outputs an amperage that varies in accordance with the oxygen concentration in the exhaust gas. The ECM uses this output voltage to determine whether the present air-fuel ratio is richer or leaner than the stoichiometric air-fuel ratio. The air-fuel ratio sensor data is read out by the Techstream.

A1A+

OX1B (0.1 to 1.0 V) (3.3 V)

ECM ECM Air-fuel Ratio Sensor Heated Oxygen Sensor

EX1B

A1A– (2.9 V)

02HEG56Y

Air-fuel Ratio Sensor Circuit (Bank 1, Sensor 1) Heated Oxygen Sensor Circuit (Bank 1, Sensor 2)

: Air-fuel ratio sensor : Heated oxygen sensor

4.2 (V) 1.0 (V)

Heated Oxygen Sensor Output Air-fuel Ratio Sensor Data Displayed on Techstream

0.1 2.2

D13N11

Rich Lean Stoichiometric Air-fuel Ratio

67 TOYOTA TUNDRA – NEW FEATURES

b. Construction

(cid:6) The basic construction of the heated oxygen sensor and the air-fuel ratio sensor is the same. However, they are divided into the cup type and the planar type, according to the different types of heater construction that are used.

(cid:6) The cup type sensor contains a sensor element that surrounds the heater. (cid:6) The planar type sensor uses alumina, which excels in heat conductivity and insulation, to integrate a sensor element with the heater, thus improving the warm-up performance of the sensor.

Heater

Platinum Electrode Atmosphere Alumina

Atmosphere Diffusion Resistance Layer

Alumina

Heater

047EG68Y

Platinum Electrode Sensor Element (Zirconia) Sensor Element (Zirconia)

(cid:1) Warm-up Specification (cid:2)

Heated Oxygen Sensor (Cup Type) Air-fuel Ratio Sensor (Planar Type)

Sensor Type Planar Type Cup Type

Warm-up Time Approx. 10 sec. Approx. 30 sec.

68 TOYOTA TUNDRA – NEW FEATURES

6) Crankshaft Position, Camshaft Position and VVT Sensors

a. General

(cid:6) Magnetic Resistance Element (MRE) sensors are used for the crankshaft position, camshaft position, and VVT sensors.

(cid:6) The timing rotor for the crankshaft position sensor is installed on the back end of the crankshaft. The timing rotor has 34 teeth, with 2 teeth missing, at 10(cid:4) intervals. Based on these teeth, the crankshaft position sensor transmits crankshaft position signals (NE signal) consisting of 33 high and low output pulses every 10(cid:4) per revolution of the crankshaft, and 1 high and low output pulse every 30(cid:4). The ECM uses the NE signal for detecting the crankshaft position as well as for detecting the engine speed. It uses the missing teeth signal to determine the top dead center.

(cid:6) The camshaft position sensor uses a timing rotor installed on the front end of the intake camshaft sprocket of the left bank. Based on the timing rotor, the sensor outputs camshaft position signals (G2 signal) consisting of 3 (3 high output, 3 low output) pulses for every 2 revolutions of the crankshaft. The ECM compares the G2 and NE signals to detect the camshaft position and identify the cylinder. (cid:6) The VVT sensors (intake and exhaust) use timing rotors installed on the intake and exhaust camshafts of each bank. Based on the timing rotors, the sensors output VVT position signals consisting of 3 (3 high output, 3 low output) pulses for every 2 revolutions of the crankshaft. The ECM compares these VVT position signals and the NE signal to detect the actual valve timing.

04E1EG54Z

04E1EG55Z

VVT Sensor (Intake) Camshaft Position Sensor

VVT Sensor (Exhaust) Timing Rotor

VVT Sensor (Bank 1) Camshaft Position Sensor

Timing Rotor

12DEG16I

Crankshaft Position Sensor

(cid:1) Wiring Diagram (cid:2)

69 TOYOTA TUNDRA – NEW FEATURES

VCV2

NE+ ECM Crankshaft Position Sensor NE–

036EG110TE

Timing Rotor

(cid:1) Sensor Output Waveforms (cid:2)

Crankshaft Position Sensor Circuit

VVT Sensor Signal Plate (720(cid:4) CA) VVT Variable Timing Range

VVT Sensor*

40(cid:4) CA

230(cid:4) CA 230(cid:4) CA 140(cid:4) CA

60(cid:4) CA

Camshaft Position Sensor Signal Plate (720(cid:4) CA)

120(cid:4) CA 180(cid:4) CA

Crankshaft Position Sensor

180(cid:4) CA 120(cid:4) CA 60(cid:4) CA

360(cid:4) CA 360(cid:4) CA

Crankshaft Position Sensor

04E1EG71C

10(cid:4) CA 30(cid:4) CA

*: This is an example of an output waveform of the VVT sensor (Bank 1, Intake).

70 TOYOTA TUNDRA – NEW FEATURES

b. MRE Type Sensor

(cid:6) The MRE type sensor consists of an MRE, a magnet and a sensor. (cid:6) The direction of the magnetic field changes due to the profile (protruding and non-protruding portions) of the timing rotor, which passes by the sensor. As a result, the resistance of the MRE changes, and the output voltage to the ECM changes to high or low. The ECM detects the crankshaft and camshaft positions based on this output voltage.

(cid:6) The differences between the MRE type sensor and the pick-up coil type sensor used on the conventional models are as follows:

– The MRE type sensor outputs a constant level of high and low digital signals regardless of the engine speed. Therefore, the MRE type sensor can detect the positions of the crankshaft and camshaft at an early stage of cranking.

(cid:1) MRE Type and Pick-up Coil Type Output Waveform Image Comparison (cid:2)

– The pick-up coil type sensor outputs analog signals with levels that change with the engine speed.

No Detection

Engine Speed Engine Speed

Analog Output

232CH41

Digital Output Sensor Output Sensor Output

Pick-up Coil Type MRE Type

71 TOYOTA TUNDRA – NEW FEATURES

7) Accelerator Pedal Position Sensor

The non-contact type accelerator pedal position sensor uses a Hall IC, which is mounted on the accelerator pedal arm.

(cid:6) The magnetic yoke mounted at the base of the accelerator pedal arm moves around the Hall IC in accordance with the amount of effort applied to the accelerator pedal. The Hall IC converts the changes in the magnetic flux that occur into electrical signals, and outputs them in the form of accelerator pedal position signals to the ECM.

(cid:6) This accelerator pedal position sensor includes 2 Hall ICs and circuits for the main and sub signals. It converts the accelerator pedal depression angles into 2 electric signals with differing characteristics and outputs them to the ECM.

Hall IC

Sensor Housing

Magnetic Yoke

04E0EG19C

Accelerator Pedal Arm

VCPA EPA VPA

5 Hall IC

VPA2

Output Voltage VPA Hall IC ECM

Magnetic Yoke

EPA2

VCP2

082EG12Y

Fully Closed Fully Open Accelerator Pedal Depressed Angle

285EG72

Accelerator Pedal Arm

Accelerator Pedal Position Sensor

72 TOYOTA TUNDRA – NEW FEATURES

8) Throttle Position Sensor

The non-contact type throttle position sensor is mounted on the throttle body, and it uses a Hall IC.

(cid:6) The Hall IC is surrounded by a magnetic yoke. The Hall IC converts the changes that occur in the magnetic flux into electrical signals, and outputs them in the form of throttle valve position signals to the ECM.

(cid:6) The Hall IC contains circuits for the main and sub signals. It converts the throttle valve opening angle into 2 electrical signals that have differing characteristics and outputs them to the ECM.

Magnetic Yoke

Hall IC

Magnetic Yoke

12CEG52Y

Cross Section

Throttle Position Sensor

Magnetic Yoke

VTA1

V 5

ETA

Hall IC

VTA2

VCTA

Hall IC

VTA2

Output Voltage VTA1 ECM

Throttle Valve Fully Closed

Throttle Valve Fully Open

230LX12

0 90(cid:4)

082EG14Y

Throttle Valve Opening Angle

73 TOYOTA TUNDRA – NEW FEATURES

Electronic Throttle Control System-intelligent (ETCS-i)

1) General

(cid:6) In the conventional throttle body, the throttle valve angle is determined invariably by the amount of accelerator pedal effort. In contrast, ETCS-i uses the ECM to calculate the optimal throttle valve angle that is appropriate for the respective driving condition and uses a throttle control motor to control the angle.

(cid:1) System Diagram (cid:2)

(cid:6) In case of an abnormal condition, this system transfers to the fail-safe mode.

Skid Control ECU Main Body ECU (Driver Side Junction Block) CAN (V Bus)

Throttle Body Mass Air Flow Meter

Throttle Valve

Accelerator Pedal Position Sensor Throttle Control Motor

Throttle Position Sensor Crankshaft Position Sensor

ECM

Camshaft Position Sensor

Cruise Control Main Switch* No. 1 to 8 Ignition Coils (with Igniter)

VVT Sensors

12DEG10I

No. 1 to 8 Fuel Injectors Engine Coolant Temperature Sensor

*: Models with cruise control system

74 TOYOTA TUNDRA – NEW FEATURES

2) Control

a. General

The ETCS-i consists of the following functions:

(cid:6) Normal Throttle Control (Non-linear Control) (cid:6) Idle Speed Control (ISC) (cid:6) TRAC (Active Traction Control/A-TRAC*1) (cid:6) Vehicle Stability Control (VSC) Coordination Control (cid:6) Cruise Control*2 (cid:6) TOW/HAUL Control*3

b. Normal Throttle Control (Non-linear Control)

(cid:1) Conceptual Diagrams of Engine Control during Acceleration and Deceleration (cid:2)

This control optimizes the throttle valve angle to an angle that is appropriate for driving conditions such as the amount of accelerator pedal effort and the engine speed, in order to achieve excellent throttle control and comfort in all operating ranges.

: With control : Without control

(cid:4)

Vehicle’s Longitudinal G

(cid:4) Ignition Timing

0 (cid:4)

Throttle Valve Opening Angle

0 (cid:4)

Accelerator Pedal Depressed Angle

00MEG38Y

0 Time (cid:3)

75 TOYOTA TUNDRA – NEW FEATURES

c. Idle Speed Control

The ECM controls the throttle valve in order to constantly maintain an ideal idle speed.

d. TRAC/A-TRAC*1

As part of the A-TRAC, the throttle valve opening angle is reduced by a demand signal sent from the skid control ECU to the ECM. This demand signal is sent if an excessive amount of slippage occurs at a drive wheel, thus ensuring vehicle stability and applying an appropriate amount of power to the road.

e. VSC Coordination Control

In order to bring the effectiveness of the VSC into full play, the throttle valve angle is regulated through a coordination control by the skid control ECU and the ECM.

f. Cruise Control*2

The ECM directly actuates the throttle valve for operation of the cruise control.

g. Tow/Haul Control*3

When the tow/haul control is operating, the throttle valve opening angle relationship to the accelerator pedal angle is increased. As a result, during tow/haul control, acceleration performance is ensured.

*1: 4WD models *2: Models with cruise control system *3: Models with towing package

76 TOYOTA TUNDRA – NEW FEATURES

3) Fail-safe Operation due to Accelerator Pedal Position Sensor Trouble

(cid:6) The accelerator pedal position sensor is comprised of 2 (main, sub) sensor circuits. (cid:6) If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between these two sensor circuits and switches into a fail-safe mode. In this fail-safe mode, the remaining circuit is used to calculate the accelerator pedal opening, in order to operate the vehicle under fail-safe mode control.

ECM

Accelerator Pedal Position Sensor

Open

Throttle Valve

Main Sub

Throttle Control Motor

Main Sub Throttle Position Sensor

199EG45

Return Spring

Throttle Body Accelerator Pedal

(cid:6) If both circuits malfunction, the ECM detects the abnormal signal voltage from these two sensor circuits and discontinues the throttle control. At this time, the vehicle can be driven within its idling range.

Closed by Return Spring

Accelerator Pedal Position Sensor

ECM

Throttle Valve

Throttle Control Motor

Main Sub

Main Sub Throttle Position Sensor

Return Spring

199EG46

Accelerator Pedal Throttle Body

77 TOYOTA TUNDRA – NEW FEATURES

4) Fail-safe Operation Caused by Throttle Position Sensor Trouble

(cid:6) The throttle position sensor is comprised of 2 (main, sub) sensor circuits. (cid:6) If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between these 2 sensor circuits, cuts off the current to the throttle control motor, and switches to a fail-safe mode.

(cid:6) Then, the force of the return spring causes the throttle valve to return and stay at the prescribed base opening position. At this time, the vehicle can be driven in the fail-safe mode while the engine output is regulated through control of the fuel injection and ignition timing in accordance with the accelerator pedal position.

(cid:6) The same control as above is effected if the ECM detects a malfunction in the throttle control motor system.

Accelerator Pedal Position Sensor

Return to Prescribed Angle

Fuel Injectors ECM Ignition Coils

Main Sub

Throttle Valve

Main Sub

Throttle Position Sensor

199EG47

Return Spring Throttle Control Motor

Accelerator Pedal Throttle Body

78 TOYOTA TUNDRA – NEW FEATURES

Dual Variable Valve Timing-intelligent (Dual VVT-i) System

1) General

Camshaft Timing OCV* (Bank 2, Exhaust)

Camshaft Timing OCV* (Bank 2, Intake)

VVT Sensor (Bank 2, Exhaust)

VVT Sensor (Bank 2, Intake)

Camshaft Position Sensor

VVT Sensor (Bank 1, Intake)

VVT Sensor (Bank 1, Exhaust)

(cid:6) The Dual VVT-i system is designed to control the intake and exhaust camshafts within a range of 40(cid:4) and 32(cid:4) respectively (of crankshaft angle) to provide valve timing optimally suited to the engine operating conditions. This improves torque in all the speed ranges as well as increasing fuel economy and reducing exhaust emissions.

ECM

Crankshaft Position Sensor Camshaft Timing OCV* (Bank 1, Exhaust)

Camshaft Timing OCV* (Bank 1, Intake)

(cid:6) Mass Air Flow Meter (cid:6) Throttle Position Sensor (cid:6) Vehicle Speed Signal

12CEG43I

Engine Coolant Temperature Sensor

*: Oil Control Valve

(cid:6) By using the engine speed, intake air mass, throttle position and engine coolant temperature, the ECM calculates the optimal valve timing for each driving condition and controls the camshaft timing oil control valves. In addition, the ECM uses signals from the intake and exhaust VVT sensors for each bank and the crankshaft position sensor to detect the actual valve timing, thus providing feedback control to achieve the target valve timing.

ECM Crankshaft Position Sensor

Camshaft Timing Oil Control Valve

Camshaft Position Sensor Target Valve Timing

Engine Coolant Temp. Sensor

Mass Air Flow Meter Duty Cycle Control Throttle Position Sensor Feedback

Correction

04E1EG66C

VVT Sensors Actual Valve Timing

Vehicle Speed Signal

79 TOYOTA TUNDRA – NEW FEATURES

2) Effectiveness of Dual VVT-i System

Operation

Condition Objective Effect Timing/ Position

TDC

IN (cid:6) Stabilized idle Most Retarded Position EX IN During Idling Eliminating overlap to reduce blow back to the intake side. speed (cid:6) Better fuel economy EX Most Advanced Position BDC 12CEG31Y

IN Retarded

EX IN

12CEG32Y

overlap EX Retarded In Low Speed Range with Light to Medium Load (cid:6) Better fuel economy (cid:6) Improved emission control Retarding the intake valve close timing and reducing pumping loss. Increasing and internal EGR.

IN Advanced

EX IN

12CEG33Y

Improved torque in low to medium speed range side, EX Advanced In Low to Medium Speed Range with Heavy Load Advancing the intake timing, valve close intake air reducing the to blow back intake and improving volumetric efficiency.

IN Retarded

EX IN Improved output

12CEG34Y

In High Speed Range with Heavy Load EX Advanced Retarding the intake valve close timing and improving volumetric efficiency using the inertia force of the intake air.

IN Most Retarded Position

12CEG31Y

EX IN At Low Temperatures (cid:6) Stabilized fast idle speed (cid:6) Better fuel economy EX as Most Advanced Position Eliminating overlap to reduce blow back to the intake side. Fixing valve timing at low extremely temperatures and increasing the control the range temperature rises.

12CEG31Y

IN (cid:6) Upon Most Retarded Position EX IN Improved startability Starting (cid:6) Stopping Engine Controlling valve timing and fixing it to the optimal timing for engine start. EX Most Advanced Position

80 TOYOTA TUNDRA – NEW FEATURES

3) Construction

a. VVT-i Controller (cid:6) This controller consists of an outer housing driven by the timing chain sprocket, and a vane coupled to each camshaft.

(cid:6) The intake side uses a VVT-i controller with 3 vanes, and the exhaust side uses one with 4 vanes. (cid:6) When the engine stops, the intake side VVT-i controller is locked at the most retarded angle by its lock pin, and the exhaust side controller is locked at the most advanced angle. This ensures excellent engine startability.

(cid:6) The oil pressure sent from the advance or retard side passages of the intake and exhaust camshafts causes rotation of the VVT-i controller vane sub-assembly relative to the timing chain sprocket, to vary the valve timing continuously.

(cid:1) Intake Side VVT-i Controller (cid:2)

(cid:6) An advance assist spring is provided on the exhaust side VVT-i controller. This helps to apply torque in the advanced angle direction so that the vane lock pin securely engages with the housing when the engine stops.

Timing Chain Sprocket

Vane (Coupled to Intake Camshaft)

Outer Housing

Timing Rotor

Intake Camshaft

Engine Operating Engine Stopped

0140EG59Z

Oil Pressure

(cid:1) Exhaust Side VVT-i Controller (cid:2)

Lock Pin

Timing Chain Sprocket

Lock Pin

Outer Housing

Exhaust Camshaft

281EG47

Vane (Fixed on Exhaust Camshaft)

Advanced Assist Spring

81 TOYOTA TUNDRA – NEW FEATURES

b. Camshaft Timing Oil Control Valve

This camshaft timing oil control valve controls the spool valve using duty cycle control from the ECM. This allows hydraulic pressure to be applied to the VVT-i controller advance or retard side. When the engine is stopped, the camshaft timing oil control valve (intake) will move to the retard position, and the camshaft timing oil control valve (exhaust) will move to the advance position.

To VVT-i Controller (Advance Side)* To VVT-i Controller (Retard Side)*

Sleeve

080EG36S

Spring Drain Drain Spool Valve

Oil Pressure

*: On the exhaust side oil control valve, the advance and retard sides are reversed.

82 TOYOTA TUNDRA – NEW FEATURES

4) Operation

a. Advance

(cid:1) Intake Side (cid:2)

When the camshaft timing oil control valve is positioned as illustrated below by the advance signals from the ECM, the resultant oil pressure is applied to the timing advance side vane chamber to rotate the camshaft in the timing advance direction.

Vane

ECM

238EG63

(cid:1) Exhaust Side (cid:2)

Oil Pressure Rotation Direction In Drain

Vane

ECM

281EG48

Oil Pressure Rotation Direction In Drain

83 TOYOTA TUNDRA – NEW FEATURES

b. Retard

(cid:1) Intake Side (cid:2)

When the camshaft timing oil control valve is positioned as illustrated below by the retard signals from the ECM, the resultant oil pressure is applied to the timing retard side vane chamber to rotate the camshaft in the timing retard direction.

Rotation Direction

ECM

238EG64

(cid:1) Exhaust Side (cid:2)

Oil Pressure Vane Drain In

Rotation Direction

ECM

281EG49

Vane Oil Pressure Drain In

c. Hold

After reaching the target timing, the engine valve timing is maintained by keeping the camshaft timing oil control valve in the neutral position unless the engine operating conditions change. This maintains the engine valve timing at the desired target position by preventing the engine oil from running out of the oil control valve.

84 TOYOTA TUNDRA – NEW FEATURES

Acoustic Control Induction System (ACIS)

1) General

(cid:1) System Diagram (cid:2)

The ACIS is implemented by using a bulkhead to divide the intake manifold into 2 stages, with an intake air control valve in the bulkhead being opened and closed to vary the effective length of the intake manifold in accordance with the engine speed and throttle valve opening angle. This increases the power output in all ranges from low to high speed.

ACIS Actuator

VSV (for ACIS) Intake Air Control Valve

ECM

Crankshaft Position Sensor

04E1EG59C

Throttle Position Sensor

2) Intake Air Control Valve and ACIS Actuator

Intake Air Control Valve integrated with the

12CEG24Y

The intake air control valve and ACIS intake actuator are manifold. This valve opens and closes to change the effective length of the intake manifold in 2 stages.

ACIS Actuator

85 TOYOTA TUNDRA – NEW FEATURES

3) Operation

a. When Intake Control Valve Closes (VSV On)

The ECM activates the VSV so that the negative pressure acts on the diaphragm chamber of the actuator. This closes the control valve to match the longer pulsation cycle. As a result, the effective length of the intake manifold is lengthened and the intake efficiency in the low-to-medium engine speed range under heavy load and low-to-high engine speed range under low load is improved due to the dynamic effect of the intake air, thereby increasing the power output.

Intake Air Control Valve (Closed)

Wide

Throttle Valve Opening Angle VSV On

Narrow

Low High

12CEG54I

04E1EG61C

Engine Speed : Effective intake manifold length

b. When Intake Control Valve Opens (VSV Off)

The ECM deactivates the VSV so that atmospheric air is led into the diaphragm chamber of the actuator. This opens the control valve to match the shorter pulsation cycle. When the control valve is open, the effective length of the intake manifold is shortened and peak intake efficiency is shifted. This benefits the high engine speed range under heavy load, thus providing greater output at high engine speeds.

Intake Air Control Valve (Open)

Wide VSV Off

Throttle Valve Opening Angle

Narrow

04E1EG63C

12CEG55I

Low High Engine Speed : Effective intake manifold length

86 TOYOTA TUNDRA – NEW FEATURES

EGR Control

The ECM determines the engine condition based primarily on various sensors. The ECM controls the EGR valve to regulate the amount of the EGR gas. This control does not operate when the engine is cold.

EGR Valve Crankshaft Position Sensor (Engine Speed)

Accelerator Pedal Position Sensor

Vacuum Sensor ECM

Engine Coolant Temperature Sensor EGR Cooler

Engine Mass Air Flow Meter

12CEG41Y

Exhaust Pipe

87 TOYOTA TUNDRA – NEW FEATURES

Fuel Pump Control

1) General

In this vehicle, there are 2 types of fuel pump controls. The fuel pump is controlled to an optimum speed to match the engine operating conditions, and the fuel pump operation is stopped when the SRS airbags deploy.

(cid:6) The ECM transmits a fuel pump operation request signal to the fuel pump ECU that corresponds to the engine operating conditions. The fuel pump ECU receives this request signal and controls the speed of the fuel pump in 3 stages. As a result, under light engine loads, fuel pump speed is kept low to reduce electric power loss.

(cid:1) System Diagram (cid:2)

(cid:6) A fuel cut control is used to stop the fuel pump when any of the SRS airbags deploys. In this control, if an airbag deployment signal from the center airbag sensor assembly is detected by the ECM, the ECM will turn off the circuit opening relay. As a result, the power supply to the fuel pump ECU is stopped, causing the fuel pump to stop operating. After the fuel cut control has been activated, turning the ignition switch from off to on cancels the fuel cut control, and the engine can be restarted.

IG2 Relay EFI Main Relay

Circuit Opening Relay

CAN (V Bus)

Front Airbag Sensors (RH and LH)

Fuel Pump Operation Request ECM Rear Floor Side Airbag Sensors (RH and LH) Fuel Pump Center Airbag Sensor Assembly Fuel Pump ECU Diagnosis Signal

Side Airbag Sensor (RH or LH)

080EG27S

Rear Airbag Sensor (RH or LH)

88 TOYOTA TUNDRA – NEW FEATURES

2) Fuel Pump ECU

(cid:6) The fuel pump ECU controls fuel pump speed by receiving a duty cycle signal (FPC terminal input) from the ECM, and control is performed in 3 stages.

(cid:6) The fuel pump ECU also detects failures in the input and output circuits at the fuel pump ECU and transmits the failure status to the ECM.

Fuel Pump Operation Request

FPC Fuel Pump Duty Cycle Signal

ECM Fuel Pump ECU

Diagnosis Signal

04E0EG24C

(cid:1) FPC Terminal Input (cid:2)

FPC Input Signal (Duty Cycle Signal) Fuel Pump Speed

04E0EG25C

12.3 ms

8.2 ms

+B High GND

Middle

04E0EG26C

12.3 ms

4.1 ms

+B GND

Low +B

12CEG50I

GND

Stop

04E0EG28C

GND

89 TOYOTA TUNDRA – NEW FEATURES

Air Injection System

1) General

To ensure the proper warm-up performance of the Three-Way Catalytic converters (TWCs) after starting a cold engine, an air injection system is used.

(cid:6) In this system, both bank 2 (right bank) and bank 1 (left bank) have an air pump, an air injection control driver, an air switching valve, and an air pressure sensor. Control of the right bank and left bank is performed independently. Two pumps are used to increase the amount of air supplied, shortening the catalyst warm-up time.

(cid:6) The ECM estimates the amount of air injected to the TWCs based on signals from the mass air flow

(cid:1) Operation Conditions (cid:2)

meter in order to regulate the air injection time. (cid:6) Air is injected under the following conditions:

Engine Coolant Temperature

(cid:1) System Diagram (cid:2)

Pump Actuation Request

Valve Actuation Request Diagnosis Signal

Air Injection Control Driver

Engine Coolant Temperature Sensor

Air Pressure Sensor

Intake Air Temperature 5(cid:4)C to 45(cid:4)C (41(cid:4)F to 113(cid:4)F) 5(cid:4)C (41(cid:4)F) or more

Air Switching Valve

To Exhaust Manifold

Air Pump

Air

Mass Air Flow Meter

ECM

Intake Air Temperature Sensor

Pump Actuation Request Valve Actuation Request

Diagnosis Signal

Air Injection Control Driver

Air Pressure Sensor

Air Switching Valve

Bank 2 (Right Bank)

To Exhaust Manifold

Air Pump

12CEG25Y

Air

Bank 1 (Left Bank)

90 TOYOTA TUNDRA – NEW FEATURES

2) Construction and Operation

a. Air Pump

Each air pump consists of a DC motor, an impeller and an air filter.

(cid:6) The air pump supplies air into an air injection control valve using its impeller. (cid:6) The air filter is maintenance-free. (cid:6) The air pumps for bank 1 and bank 2 have the same basic structure and function.

Air In Air Filter Air Out Air In

Impeller Air Out

DC Motor

Air Pump (Bank 2)

04E0EG30C

04E0EG70C

Air Pump (Bank 1) Cross Section

b. Air Switching Valve

(cid:6) The air switching valve is operated by a DC motor to control air injection and prevent back-flow of exhaust gas. Opening timing of the valve is synchronized with the operation timing of the air pump.

(cid:6) An air pressure sensor is built into the corresponding air switching valve. (cid:6) The air switching valves for bank 1 and bank 2 have the same basic structure and function.

Air Out Air Switching Valve (Bank 1) DC Motor Air Switching Valve (Bank 2) Valve Air Out

Air In

Air In Air Out

12CEG26Y

Cross Section (for Bank 1)

91 TOYOTA TUNDRA – NEW FEATURES

c. Air Pressure Sensor

(cid:6) The air pressure sensor consists of a semiconductor, which has a silicon chip that changes its electrical resistance when pressure is applied to it. The sensor converts the pressure into an electrical signal, and sends it to the ECM in an amplified form.

(cid:6) The air pressure sensors for bank 1 and bank 2 have the same basic structure and function.

(V) Sensor Unit

Air Pressure of Electric Air Pump 4.5

Output Voltage

0.5

12CEG27Y

45 150 (kPa) 257MA22 Air Pressure (Absolute Pressure)

The ECM detects operation of the air injection system based on signals from the air pressure sensor as follows:

1) When the air pump is on and the air switching valve is closed, the pressure is stable.

2) When the air pump is on and the air switching valve is open, the pressure drops slightly and becomes unstable because of exhaust pulses.

3) When the air pump is off and the air switching valve is closed, the pressure remains at atmospheric pressure.

4) When the air pump is off and the air switching valve is open, the pressure drops below atmospheric pressure and becomes unstable because of exhaust pulses.

Example: 1 Example: 2

Pressure Pressure

Time Time

0 (Atmospheric Pressure) 0 (Atmospheric Pressure) Air Pump: On Air Switching Valve: Closed Air Pump: On Air Switching Valve: Open

Example: 3 Example: 4

Pressure Pressure

Time Time

273GX81

0 (Atmospheric Pressure) 0 (Atmospheric Pressure) Air Pump: Off Air Switching Valve: Closed Air Pump: Off Air Switching Valve: Open

92 TOYOTA TUNDRA – NEW FEATURES

d. Air Injection Control Driver

(cid:6) A semiconductor type air injection control driver is used. Activated by the ECM, this driver actuates the air pump and the air switching valve.

(cid:6) The air injection control driver also detects failures in the input and output circuits of the air injection driver and transmits the failure status to the ECM via duty cycle signals.

(cid:6) The air injection control drivers for bank 1 and bank 2 have the same basic structure and function. The following system chart shows the bank 1 (left bank):

Air Pump Actuation Request AIRP SIP

Air Pump VP

Air Switching Valve Actuation Request

AIRV SIV ECM Air Injection Control Driver

Air Switching Valve Duty Cycle Signal

12CEG28Y

(cid:1) DI Terminal Output (cid:2)

AIDI DI

Condition AIRP AIRV Output (Duty Cycle Signal)

273GX28

— — Open circuit in line between AIDI and DI terminals. GND

273GX29

— — Failure in line between ECM terminals and air injection control driver. GND

273GX30

200 ms Duty 20% — — Output failure at air injection control driver. (Failure in air pump actuation circuit) GND

273GX31

Duty 40% — — GND Output failure at air injection control driver. (Failure in air switching valve actuation circuit)

273GX32

Duty 60% — — GND Overheat failure of air injection control driver.

273GX33

Duty 80% On On GND

Normal Off Off

273GX29

On Off GND Off On

93 TOYOTA TUNDRA – NEW FEATURES

Starter Control (Cranking Hold Function)

1) General

(cid:6) Once the ignition switch is turned to the START position, this control continues to operate the starter until the engine starts, without having to hold the ignition switch in the START position. This prevents starting failures.

(cid:1) System Diagram (cid:2)

(cid:6) When the ECM detects a start signal from the ignition switch, this system monitors the engine speed (NE) signal and continues to operate the starter until it determines that the engine has started.

ACC Cut Relay ECM

ACCR

STSW

Ignition Switch STAR

Park / Neutral Position Switch

Starter

STA

Battery Starter Relay

00SEG55Y

(cid:6) Engine Speed Signal (cid:6) Engine Coolant Temperature Signal

94 TOYOTA TUNDRA – NEW FEATURES

2) Operation

(cid:6) As indicated in the following timing chart, when the ECM detects a start signal from the ignition switch, it energizes the starter relay to operate the starter. If the engine is already running, the ECM will not energize the starter relay.

(cid:6) After the starter operates and the engine speed becomes higher than approximately 500 rpm, the ECM determines that the engine has started and stops the operation of the starter.

(cid:6) If the engine does not start due to a failure, the starter operates as long as its maximum continuous operation time and stops automatically. The maximum continuous operation time varies depending on the engine coolant temperature condition.

(cid:6) This system cuts off the current that powers the accessories while the engine is cranking to prevent the accessory illumination from operating intermittently due to the unstable voltage associated with the cranking of the engine.

(cid:6) This system has the following protections:

(cid:1) Timing Chart (cid:2)

– In the event that the starter begins to operate, but cannot detect the engine speed signal, the ECM will stop the starter operation immediately. However, if the ignition switch is held in the START position, the starter continues to operate.

START

Maximum Continuous Operation Time

Ignition Switch Position On

On Starter Relay

Off On Accessory Power Off

Successful Starting of Engine

Failed Starting of Engine Engine Speed Signal (NE)

00SEG57Y

ECM determines that the engine has started successfully when the engine speed is approximately 500 rpm.

95 TOYOTA TUNDRA – NEW FEATURES

Evaporative Emission Control System

1) General

The evaporative emission control system prevents the fuel vapors created in the fuel tank from being released directly into the atmosphere. The canister stores the fuel vapors that have been created in the fuel tank.

(cid:6) The ECM controls the purge VSV in accordance with the driving conditions in order to direct the fuel vapors into the engine, where they are burned.

(cid:6) In this system, the ECM checks for evaporative emission leaks and outputs a Diagnostic Trouble Code (DTC) in the event of a malfunction. An evaporative emission leak check consists of an application of vacuum to the evaporative emissions system and monitoring the system for changes in pressure in order to detect a leakage.

(cid:6) This system consists of the purge VSV, canister, refueling valve, canister pump module, and ECM. (cid:6) An On-board Refueling Vapor Recovery (ORVR) function is provided in the refueling valve. (cid:6) A canister pressure sensor has been included with the canister pump module. (cid:6) A canister filter has been provided on the fresh air line. This canister filter is maintenance-free. (cid:6) The following are the typical conditions necessary to enable an evaporative emission leak check:

Typical Enabling Condition

(cid:6) 5 hours have elapsed after the engine has been turned off* (cid:6) Altitude: Below 2400 m (8000 feet) (cid:6) Battery Voltage: 10.5 V or more (cid:6) Power Source: Off (cid:6) Engine Coolant Temperature: 4.4(cid:4)C to 35(cid:4)C (40(cid:4)F to 95(cid:4)F) (cid:6) Intake Air Temperature: 4.4(cid:4)C to 35(cid:4)C (40(cid:4)F to 95(cid:4)F)

*: If the engine coolant temperature does not drop below 35(cid:4)C (95(cid:4)F), this time should be extended to 7 hours. Even after that, if the temperature is not less than 35(cid:4)C (95(cid:4)F), the time should be extended to 9.5 hours.

Service Tip

The canister pump module performs a fuel evaporative emission leakage check. This check is done approximately 5 hours after the engine is turned off. Sound may be heard coming from underneath the luggage compartment for several minutes. This does not indicate a malfunction. (cid:6) The pinpoint pressure test procedure is implemented by pressurizing the fresh air line that runs from the canister pump module to the air filler neck. For details, refer to the 2010 TOYOTA TUNDRA Repair Manual.

96 TOYOTA TUNDRA – NEW FEATURES

2) System Diagram

To Intake Manifold Refueling Valve

Purge VSV

Restrictor Passage

Canister Canister Pump Module Fuel Tank

Purge Air Line

Vent Valve Canister Filter

Fresh Air Line

ECM Leak Detection Pump

036EG116TE

Canister Pressure Sensor

3) Layout of Main Components

Refueling Valve Canister Pump Module (cid:6) Vent Valve (cid:6) Leak Detection Pump (cid:6) Canister Pressure Sensor Canister

Front

Canister Filter

Purge VSV

12DEG11I

Fresh Air Line

Purge Air Line

97 TOYOTA TUNDRA – NEW FEATURES

4) Function of Main Components

Function Component

Canister Contains activated charcoal to absorb the fuel vapors created in the fuel tank.

Controls the flow rate of the fuel vapors from the fuel tank to the canister when the system is purging or during refueling.

Refueling Valve

Restrictor Passage Prevents a large amount of vacuum during purge operation or system monitoring operation from affecting the pressure in the fuel tank.

Fresh Air Line Fresh air goes into the canister and the cleaned drain air goes out into the atmosphere.

Vent Valve Opens and closes the fresh air line in accordance with the signals from the ECM.

Leak Detection Pump Applies vacuum pressure to the evaporative emission system in accordance with the signals from the ECM. Canister Pump Module

Canister Pressure Sensor Detects the pressure in the evaporative emission system and sends the signals to the ECM.

Purge VSV

Opens in accordance with the signals from the ECM when the system is purging, in order to send the fuel vapors that have been absorbed by the canister into the intake manifold. In system monitoring mode, this valve controls the introduction of the vacuum into the fuel tank.

Canister Filter Prevents dust and debris in the fresh air from entering the system.

ECM

Controls the canister pump module and the purge VSV in accordance with the signals from various sensors, in order to achieve a purge volume that suits the driving conditions. In addition, the ECM monitors the system for any leakage and outputs a DTC if a malfunction is found.

98 TOYOTA TUNDRA – NEW FEATURES

5) Construction and Operation

a. Refueling Valve

(cid:6) The refueling valve consists of chamber A, chamber B, and the restrictor passage. A constant atmospheric pressure is applied to chamber A.

(cid:6) During refueling, the internal pressure of the fuel tank increases. This pressure causes the refueling valve to lift up, allowing the fuel vapors to enter the canister.

(cid:6) The restrictor passage prevents the large amount of vacuum created during purge operation or system monitoring operation from entering the fuel tank, and limits the flow of the fuel vapors from the fuel tank to the canister. If a large volume of fuel vapors enters the intake manifold, it will affect the air-fuel ratio control of the engine. Therefore, the role of the restrictor passage is to help prevent this from occurring.

Chamber A

Fresh Air Line

Refueling Valve (Open)

Chamber B Canister

To Fuel Tank From Fuel Tank

Internal Pressure Positive Pressure (Fuel Tank Pressure) Restrictor Passage Negative Pressure (Intake Manifold Pressure) 030LS05C During Refueling During Purge Operation or System Monitoring Operation

b. Fuel Inlet (Fresh Air Inlet)

In accordance with the change of structure of the evaporative emission control system, the location of the fresh air line inlet has been changed from the air cleaner to the vicinity of the fuel inlet. The fresh air from the atmosphere and drain air cleaned by the canister will go in or out of the system through the passages shown below:

Fuel Tank Cap

Fresh Air

To Canister

228TU119

Cleaned Drain Air Fuel Inlet Pipe

99 TOYOTA TUNDRA – NEW FEATURES

c. Canister Pump Module

(cid:6) The canister pump module consists of the vent valve, canister pressure sensor, and leak detection pump (vacuum pump and pump motor).

(cid:6) The vent valve switches the passages in accordance with the signals received from the ECM. (cid:6) A brushless type DC motor is used for the pump motor. (cid:6) A vane type vacuum pump is used.

Vent Valve Canister Pressure Sensor Fresh Air

Leak Detection Pump (cid:6) Pump Motor (cid:6) Vacuum Pump

Fresh Air

279EG25

279EG26

(cid:1) Simple Diagram (cid:2)

Canister

Canister Pump Module

Vent Valve (Off)

Fresh Air Filter

To Canister

Leak Detection Pump

Filter

Canister Pressure Sensor

036EG117TE

Reference Orifice [0.5 mm (0.020 in.) Diameter]

100 TOYOTA TUNDRA – NEW FEATURES

6) System Operation

a. Purge Flow Control

When the engine has reached predetermined parameters (closed loop, engine coolant temp. above 70(cid:4)C (158(cid:4)F), etc), stored fuel vapors are purged from the canister whenever the purge VSV is opened by the ECM. The ECM will change the duty cycle of the purge VSV, thus controlling purge flow volume. Purge flow volume is determined by intake manifold pressure and the duty cycle of the purge VSV. Atmospheric pressure is allowed into the canister to ensure that purge flow is constantly maintained whenever purge vacuum is applied to the canister.

Atmosphere To Intake Manifold

Purge VSV (Open)

036EG118TE

ECM

b. ORVR (On-board Refueling Vapor Recovery)

When the internal pressure of the fuel tank increases during refueling, this pressure causes the diaphragm in the refueling valve to lift up, allowing the fuel vapors to enter the canister. The air that has had the fuel vapors removed from it will be discharged through the fresh air line. The vent valve is used to open and close the fresh air line, and it is always open (even when the engine is stopped) except when the vehicle is in monitoring mode (the valve will be open as long as the vehicle is not in monitoring mode). If the vehicle is refueled in system monitoring mode, the ECM will recognize the refueling by way of the canister pressure sensor, which detects the sudden pressure increase in the fuel tank, and the ECM will open the vent valve.

Open

036EG119TE

Purge VSV (Closed)

101 TOYOTA TUNDRA – NEW FEATURES

c. EVAP Leak Check

i) General

(cid:1) Timing Chart (cid:2)

On (Open)

The EVAP leak check operates in accordance with the following timing chart:

Purge VSV

Off (Closed)

Vent Valve

Off (Vent)

Off

Leak Detection Pump

Atmospheric Pressure

System Pressure

0.02 in. Pressure

1) 2) 3) 4) 5) 6) 12CEG44I

Order Operation Description Time

1) 60 sec. The ECM turns the vent valve off (vent) and measures EVAP system pressure to memorize the atmospheric pressure. Atmospheric Pressure Measurement

2) 60 sec. 0.02 in. Leak Pressure Measurement The leak detection pump creates negative pressure (vacuum) through a 0.02 in. orifice and the pressure is measured. The ECM determines this as the 0.02 in. leak pressure.

3) EVAP Leak Check Within 17 min.

The leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized pressure is larger than the 0.02 in. leak pressure, the ECM determines that the EVAP system has a leak. If the EVAP pressure does not stabilize within 15 minutes, the ECM cancels EVAP monitor.

4) 10 sec. Purge VSV Monitor The ECM opens the purge VSV and measures the EVAP pressure increase. If the increase is large, the ECM interprets this as normal.

5) 60 sec. Repeat 0.02 in. Leak Pressure Measurement The leak detection pump creates negative pressure (vacuum) through the 0.02 in. orifice and the pressure is measured. The ECM determines this as the 0.02 in. leak pressure.

6) Final Check — The ECM measures the atmospheric pressure and records the monitor result.

102 TOYOTA TUNDRA – NEW FEATURES

ii) Atmospheric Pressure Measurement

1) When the ignition switch is turned off, the purge VSV and the vent valve are turned off. Therefore, atmospheric pressure is introduced into the canister.

2) The ECM measures the atmospheric pressure based on the signals provided by the canister pressure sensor.

3) If the measurement value is outside the standard pressure, the ECM actuates the leak detection pump in order to monitor the changes in the pressure.

Atmosphere

Purge VSV (Off)

Vent Valve (Off)

Canister Pump Module

Leak Detection Pump (Off)

Canister Pressure Sensor

036EG120TE

On (Open)

ECM

Purge VSV

Off (Closed)

Vent Valve

On Off (Vent)

Leak Detection Pump

Off

Atmospheric Pressure

System Pressure

0.02 in. Pressure

D13N22

Atmospheric Pressure Measurement

103 TOYOTA TUNDRA – NEW FEATURES

iii) 0.02 in. Leak Pressure Measurement

1) The vent valve remains off, and the ECM introduces atmospheric pressure into the canister and actuates the leak detection pump in order to create a negative pressure.

2) At this time, the pressure will not decrease beyond a 0.02 in. pressure due to the atmospheric pressure that enters through a 0.02 in. diameter reference orifice.

3) The ECM compares the logic value and this pressure, and stores it as a 0.02 in. leak pressure in its memory.

4) If the measurement value is below the standard, the ECM will determine that the reference orifice is clogged and store DTC P043E in its memory.

5) If the measurement value is above the standard, the ECM will determine that a high flow rate pressure is passing through the reference orifice and store DTC P043F, P2401 and P2402 in its memory.

Atmosphere

Purge VSV (Off)

Vent Valve (Off)

Canister Pump Module

Leak Detection Pump (On)

Canister Pressure Sensor

Reference Orifice

036EG121TE

On (Open)

ECM

Purge VSV

Off (Closed)

Vent Valve

On Off (Vent)

Leak Detection Pump

Off

Atmospheric Pressure

System Pressure

0.02 in. Pressure

0.02 in. Leak Pressure Measurement

12CEG45I

104 TOYOTA TUNDRA – NEW FEATURES

iv) EVAP Leak Check

1) While actuating the leak detection pump, the ECM turns on the vent valve in order to introduce a vacuum into the canister.

2) When the pressure in the system stabilizes, the ECM compares this pressure and the 0.02 in. pressure in order to check for a leakage.

3) If the detection value is below the 0.02 in. pressure, the ECM determines that there is no leakage.

4) If the detection value is above the 0.02 in. pressure and near atmospheric pressure, the ECM determines that there is a gross leakage (large hole) and stores DTC P0455 in its memory.

5) If the detection value is above the 0.02 in. pressure, the ECM determines that there is a small leakage and stores DTC P0456 in its memory.

Atmosphere

Vacuum

Purge VSV (Off)

Vent Valve (On)

Canister Pump Module

Leak Detection Pump (On)

Canister Pressure Sensor

036EG122TE

Reference Orifice

On (Open)

ECM

Purge VSV

Off (Closed)

Vent Valve

Off (Vent)

Leak Detection Pump

Off

Atmospheric Pressure

P0455

System Pressure

0.02 in. Pressure

P0456

Normal

EVAP Leak Check

12CEG46I

105 TOYOTA TUNDRA – NEW FEATURES

v) Purge VSV Monitor

1) After completing an EVAP leak check, the ECM turns on the purge VSV with the leak detection pump actuated, and introduces the atmospheric pressure from the intake manifold to the canister.

2) If the pressure change at this time is within the normal range, the ECM determines the condition to be normal.

3) If the pressure is out of the normal range, the ECM will stop the purge VSV monitor and store DTC P0441 in its memory.

Atmosphere

Purge VSV (On)

Vent Valve (On)

Canister Pump Module

Leak Detection Pump (Off)

Canister Pressure Sensor

Reference Orifice

036EG123TE

On (Open)

ECM

Purge VSV

Off (Closed)

Vent Valve

Off (Vent)

Leak Detection Pump

Off

Atmospheric Pressure

Normal

System Pressure

0.02 in. Pressure

12CEG47I

P0441

Purge VSV Monitor

106 TOYOTA TUNDRA – NEW FEATURES

vi) Repeat 0.02 in. Leak Pressure Measurement

1) While the ECM operates the leak detection pump, the purge VSV and vent valve turn off and a repeat 0.02 in. leak pressure measurement is performed.

2) The ECM compares the measured pressure with the pressure during EVAP leak check.

3) If the pressure during the EVAP leak check is below the measured value, the ECM determines that there is no leakage.

4) If the pressure during the EVAP leak check is above the measured value, the ECM determines that there is a small leak and stores DTC P0456 in its memory.

Atmosphere

Purge VSV (Off)

Vent Valve (Off)

Canister Pump Module

Leak Detection Pump (On)

Canister Pressure Sensor

Reference Orifice

036EG124TE

On (Open)

ECM

Purge VSV

Off (Closed)

Vent Valve

Off (Vent)

Leak Detection Pump

Off

Atmospheric Pressure

System Pressure

0.02 in. Pressure

P0456

Normal

Repeat 0.02 in. Leak Pressure Measurement

12CEG48I

107 TOYOTA TUNDRA – NEW FEATURES

Diagnosis

(cid:6) When the ECM detects a malfunction, the ECM makes a diagnosis and memorizes the failed section. Furthermore, the Malfunction Indicator Lamp (MIL) in the combination meter illuminates or blinks to inform the driver.

(cid:6) The ECM will also store the DTC of the malfunctions. The DTC can be accessed by using the Techstream. (cid:6) For details, refer to the 2010 TOYOTA TUNDRA Repair Manual.

Service Tip

To clear the DTC that is stored in the ECM, use the Techstream, disconnect the battery terminal or remove the EFI MAIN fuse and ETCS fuse for 1 minute or longer.

Fail-safe

When a malfunction is detected at any of the sensors, there is a possibility of an engine or other malfunction occurring if the ECM continues to control the engine control system in the normal way. To prevent such a problem, the fail-safe function of the ECM either relies on the data stored in memory to allow the engine control system to continue operating, or stops the engine if a hazard is anticipated. For details, refer to the 2010 TOYOTA TUNDRA Repair Manual.