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36ENGINE - 2UZ-FE ENGINEENGINE2UZ-FE ENGINE DESCRIPTIONThe engine on the Sequoia is the 2UZ-FE engine that supports the U-LEV (Ultra-Low Emission Vehicle)requirements. It is based on the 2UZ-FE engine, which is a V8, 4.7-liter, 32-valve DOHC engine that isequipped on the ’00 Toyota Tundra.This engine has been developed to realize high performance, quiet operation, and fuel economy. In addition,it has adopted the ETCS-i (Electronic Throttle Control System-intelligent) to ensure excellent controllabilityof the vehicle and to improve its comfort.164EG13164EG14

37ENGINE - 2UZ-FE ENGINE Specification Engine Type2UZ-FENo. of Cyls. & Arrangement8-Cylinder, V TypeValve Mechanism32-Valve DOHC, Belt & Gear DriveCombustion ChamberPentroof TypeManifoldsCross-FlowFuel SystemSFIcm3DisplacementBore x Stroke(cu.in.)4664 (284.5)mm (in.)94.0 x 84.0 (3.70 x 3.31)Compression Ratio9.6 : 1Max. Output(SAE-NET)179 kW @ 4800 rpm(240 HP @ 4800 rpm)Max. Torque(SAE-NET)427 N.m @ 3400 rpm(315 ft.lbf @ 3400 rpm)Open3 BTDCClose36 ABDCOpen46 BBDCClose3 ATDCIntakeValve TimingExhaustFuel Octane NumberRON91 or MoreOil Grade API SJ, EC or ILSACPerformance Curve (HP) kW200260240 180Torque220200180160140120100806040200N.m (ft.lbf)440 330420 310400 290380360 270340 250320 230300210160140120100Output8060402001000 2000 3000 4000 5000Engine Speed (rpm)196MO50

38ENGINE - 2UZ-FE ENGINE FEATURE OF 2UZ-FE ENGINEThe 2UZ-FE engine has been able to achieve the following performance through the adoption of the itemslisted below.(1) High performance and fuel economy(2) Low noise and vibration(3) Lightweight and compact design(4) Good serviceability(5) Clean emissionItem(1)An upright intake port has been adopted to improve theintake efficiency. A taper squish configuration has been adopted to improvethe combustion efficientcy. ’01Sequoia’00 ToyotaTundra - - -(2)(3) An aluminum oil pan that is integrated with stiffencershas been adopted to reduce noise and vibration.The skirt portion of the piston has been applied with tinplating to reduce friction. Inner shim type valve lifters have been adopted. Large-diameter intake and exhaust valves have beenadopted to reduce the intake and exhaust resistance. The automatic transmission oil cooler has been adoptedto the multi-plate aluminum type. The method for installing the radiator reservoir tank hasbeen simplified and its overflow pipe has been integratedwith the radiator reservoir tank. A long port intake manifold is used to improve theengine’s torque in the low-to mid speed range. Performance and serviceability have been improved byoptimizing the shape of the air cleaner. The main muffler has adopted a dual inlet pipeconfiguration to reduce exhaust resistance. 4-hole type fuel injectors have been adopted to improvethe automization of fuel. A compact fuel filter has been adopted for weightreduction. A service port has been provided for inspecting theevaporative emission control system. The vacuum type has been adopted to detect leaks in theevaporative emission control system. ETCS-i has been adopted to realize excellentcontrollability and comfort of the vehicle.A DTC (Diagnostic Trouble Code) P0128 has been addedfor indicating a thermostat malfunction.For details, refer to the 2001 Sequoia Repair Manual(Pub. No. RM832U).(5) A steel laminate type cylinder head gasket has beenadopted to ensure its reliability.The DIS (Direct Ignition System) makes ignition timingadjustment unnecessary.(4)

56ENGINE - 2UZ-FE ENGINE ENGINE CONTROL SYSTEM1. GeneralIn addition to the SFI (Sequential Multiport Fuel Injection) system and the ESA (Electronic Spark Advance)system, the ETCS-i (Electronic Throttle Control System-intelligent) has been adopted in the engine controlsystem to realize excellent vehicle maneuverability and comfort. Also, the cruise control system and the engine immobiliser system have been integrated in the ECM.The engine control system of the Sequoia’s 2UZ-FE engine and ’00 TOYOTA Tundra’s 2UZ-FE engine arecompared below.SystemOutline’01Sequoia’00 ToyotaTundraSFISequential MultiportFuel InjectionAn L-type SFI system directly detects the intake air volume witha hot-wire mass air flow meter. — — — — ESAElectronic SparkAdvanceETCS-iElectronicThrottle ControlSystem-intelligentFuel Pump ControlOxygen SensorHeater ControlAir ConditioningCut-off ControlEvaporativeEmission ControlEngine ImmobiliserDiagnosisFail-safe Ignition timing is determined by the ECM based on signalsfrom various sensors. Corrects ignition timing in response toengine knocking. The torque control correction during gear shifting has beenused to minimize the shift shock. 2 knock sensors are used to further improve knock detection.Optimally controls the throttle valve opening in accordance withthe amount of the accelerator pedal effort, and the conditions ofthe engine and the vehicle, and comprehensively controls theISC, and cruise control. For details, see page 63.The fuel pump speed is controlled by the fuel pump relay and thefuel pump resistor.A fuel cut control is adopted to stop the fuel pump when the airbagis deployed at the front or side collision.For details, see page 67.Maintains the temperature of the oxygen sensor at an appropiatelevel to increase accuracy of detection of the oxygen concetrationin the exhaust gas.By controlling the air conditioning compressor ON or OFF inaccordance with the engine condition, drivability is maintained.The ECM controls the purge flow of evaporative emission (HC)in the charcoal canister in accordance with engine conditions.Using 3 VSVs and a vapor pressure sensor, the ECM detects anyevaporative emission leakage occurring between the fuel tankand the charcoal canister through the changes in the tank pressure.For details, see page 68.Prohibits fuel delivery and ignition if an attempt is made to startthe engine with an invalid ignition key.When the ECM detects a malfunction, the ECM diagnoses andmemorizes the failed section. A DTC (Diagnostic Trouble Code) P0128 has been added forindicating a thermostat malfunction. To increase the speed for processing the signals, the 32-bitCPU of the ECM has been adopted. Accordingly, the length oftime to clear the DTC via the battery terminal has beenchanged from the previous 10 seconds to 1 minute.For details, refer to the 2001 Sequia Repair Manual (Pub. No.RM832U).When the ECM detects a malfunction, the ECM stops or controlsthe engine according to the data already stored in the memory.

57ENGINE - 2UZ-FE ENGINE2. ConstructionThe configuration of the engine control system in the 2UZ-FE engine is shown in the following chart.SENSORSMASS AIR FLOW METERCRANKSHAFT POSITON SENSORCAMSHAFT POSITION SENSORTHROTTLE POSITION AVTA2ACCELERATOR PEDALPOSITION SENSORENGINE COOLANT TEMP. SENSORVPANo.1 INJECTORNo.2 INJECTORNo.3 INJECTORNo.4 INJECTORNo.5 INJECTORNo.6 INJECTORNo.7 INJECTORNo.8 INJECTORVPA2THWESAIGT1, 4, 6, 7IGNITION COIL with IGNITERINTAKE AIR TEMP. SENSORIGF1THANo.1, 4, 6 and 7IGT2, 3, 5, 8KNOCK SENSORSIGNITION COIL with IGNITERKNKLIGF2KNKRCOMBINATION METERNo.2, 3, 5 and 8SPARK PLUGS SPARK PLUGSNo.2, 3, 5 and 8 No.1, 4, 6 and 7SPD Vehicle Speed SignalECMIGNITION SWITCH Starting Signal (ST Terminal) Ignition Signal (IG Terminal)PARK/ NEUTRAL POSITIONSWITCH Neutral Start Signal Shift Lever Position SignalAIRBAG SENSOR ASSEMBLYETCS-iSTAIGSWM , MCL , CL-NSWR, D, 2, LF / PSHEATED OXYGEN SENSOR(Bank 1, Sensor 1)OXL1HEATED OXYGEN SENSOR(Bank 2, Sensor 1)OXR1HEATED OXYGEN SENSOR(Bank 1, Sensor 2)OXL2HEATED OXYGEN SENSOR(Bank 2, Sensor 2)OXR2THROTTLE CONTROL MOTORMAGNETIC CLUTCHFUEL PUMP CONTROLFCFPRCIRCUIT OPENING RELAYFUEL PUMP RELAYOXYGEN SENSORHEATER CONTROLHTLHEATED OXYGEN SENSORHEATER (Bank 1, Sensor 1)HTRHEATED OXYGEN SENSORHEATER (Bank 2, Sensor 1)HTL2HEATED OXYGEN SENSORHEATER (Bank 1, Sensor 2)HTR2HEATED OXYGEN SENSORHEATER (Bank 2, Sensor 2)(Countinued)

58ENGINE - 2UZ-FE ENGINEAIR CONDITIONING ECUAIR CONDITIONING CONTROLAC1ACT A/ C Switch SignalAIR CONDITIONING ECUTHWOELSTAILLIGHT RELAYEVAPORATIVE EMISSIONCONTROLSTPSTOP LIGHT SWITCHVAPOR PRESSURE SENSORCCVTBPPRGPTNKVSV (for Canister Closed Valve)VSV (for Pressure Switching Valve)VSV (for EVAP)ECMUNLOCK WARNING SWITCHKSWIMLDTXCTRXCKCODETRANSPONDER KEYAMPLIFIERSKID CONTROL ECUTRCENGDATA LINK CONNECTOR 3SILTC BEFI MAIN RELAYMRELWBATTBATTERYSECURITY INDICATOR LIGHTEFI MAIN RELAYMALFUNCTION INDICATORLAMP

59ENGINE - 2UZ-FE ENGINE3. Engine Control System DiagramIgnition SwitchFuel Pump ResisterVapor PressureSensorVSV(for EVAP)Fuel Pump RelayCircuit OpeningRelayFuelFilterIntake Temp. SensorVSVfor PressureSwitch ValveFuel PumpThrottle PositionSensorMass Air Flow MeterCharcoal CanisterAccelerator PedalPosition SensorVSVfor CanisterClosed ValveInjectorInjectorIgnition Coil(with Igniter)Camshaft Position SensorIgnition Coil(with Igniter)*1*2*2Knock Sensor*2KnockSensor*2Crankshaft PositionSensorECMStarterAir ConditioningMILVehicle SpeedSensor(for Transmission)Park / Neutral Position SwitchBatteryDLC3*1: Engine Coolant Temp. Sensor*2: Heated Oxygen SensorElectronic Controlled TransmissionSolenoid Valves196EG09

60ENGINE - 2UZ-FE ENGINE4. Layout of ComponentsPark/Neutral Position SwitchCombination MeterVSV (for EVAP)Throttle PositoinSensorKnock Sensor 2Ignition Coilwith IgniterAccelerator PedalInjectorPosition SensorVSV(for Pressure Switching Valve)Fuel Pump RelayECMMass erVapor Pressure SensorDLC3Throttle Control Motor(with Magnetic Clutch)Heated Oxygen Sensor(Bank 1, Sensor 2)CrankshaftPosition SensorHeated OxygenSensor(Bank 1, Sensor 1)Camshaft PositionSensorKnock Sensor 1Heated Oxygen Sensor(Bank 2, Sensor 1)VSV(for Canister Closed Valve)Fuel Pump ResisterHeated Oxygen Sensor(Bank 2, Sensor 2)196EG10

61ENGINE - 2UZ-FE ENGINE5. Main Components of Engine Control SystemGeneralThe main components of the 2UZ-FE engine control system are as follows:ComponentOutlineQuantityHot-Wire Type1Crankshaft Position Sensor (Rotor Teeth)Pick-Up Coil Type (36-2)1Camshaft Position Sensor (Rotor Teeth)Pick-Up Coil Type (1)1Throttle Position SensorLinear Type2Accelerator Pedal Position SensorLinear Type2Built-In Piezoelectric Type2With Heater Type44-Hole Type8Mass Air Flow MeterKnock SensorOxygen Sensor(Bank 1, Sensor 1)(Bank 1, Sensor 2)(Bank 2, Sensor 1)(Bank 2, Sensor 2)InjectorMass Air Flow MeterThe 2UZ-FE engine adopts the hot-wire typemass air flow meter designed for direct electricalmeasurement of the intake air mass flow.This mass air flow meter offers superior measuring precision and its plastic housing is shaped forminimal flow resistance. It has the following features: Compact and lightweightThe pressure loss caused by this sensor issmall and offers only slight intake air flow resistance.Intake AirTemp. SensorHot Wire Superior response and measuring accuracy. Ability to measure a wide airflow range. Having no mechanical functions, it offers asuperior durability.140EG45

62ENGINE - 2UZ-FE ENGINECrankshaft Position SensorThe crankshaft position sensor is mounted on theoil pump body as illustrated below.The rotor’s teeth are spaced 10 apart, accordingto crankshaft angle, but since there are 2 teethmissing, as illustrated below, there is a total of 34teeth.Accordingly, the ECM can detect the crankshaftangle in addition to the crankshaft speed.Timing RotorCrankshaft Position Sensor151EG18Camshaft Position SensorThe camshaft position sensor is mounted on theleft bank cylinder head. To detect the camshaftposition, a protrusion that is provided on the timing pulley is used to generate 1 pulse for every 2revolutions of the crankshaft.Timing RotorCamshaft Position Sensor156EG26

63ENGINE - 2UZ-FE ENGINE6. ETCS-i (Electronic Throttle Control System-intelligent)General The ETCS-i, which realizes excellent throttle control in all the operating ranges, has been adopted. In the conventional throttle body, the throttle valve opening is determined invariably by the amount ofthe accelerator pedal effort. In contrast, the ETCS-i uses the ECM to calculate the optimal throttle valveopening that is appropriate for the respective driving condition and uses a throttle control motor to controlthe opening. The ETCS-i controls the ISC (Idle Speed Control) system, the cruise control system, the TRAC (TractionControl), and the VSC (Vehicle Skid Control) system. A duplicate system is provided to ensure a high level of reliability, and the system shuts off in case ofan abnormal condition. Even when the system is shut off, the accelerator pedal can be used to operatethe vehicle in the limp mode.Accelerator PedalPosition SensorThrottle ValveThrottle MSkidControlECU150EG41

64ENGINE - 2UZ-FE ENGINEConstructionLimp Mode LeverThrottle ValveThrottle Position SensorAccelerator PedalPosition SensorThrottle ControlMotorMagnetic Clutch156EG301) Accelerator Pedal Position SensorThe accelerator pedal position sensor, which is mounted on the throttle body, is integrated with thethrottle lever, which is connected to the cable that extends from the accelerator pedal.The accelerator pedal position sensor converts the amount of accelerator pedal effort into two types ofelectrical signals with distinct output characteristics. The signals are then input into the ECM.OpenE2VPA2 VPAOutput r Pedal Depressed Angle150EG392) Throttle Position SensorThe throttle position sensor converts the throttle valve opening into an electrical signal and inputs intothe ECM. The output characteristics are the same as those of the accelerator positon pedal sensor.3) Throttle Control MotorA DC motor with excellent response and minimal power consumption is used for the throttle control motor. The ECM performs the duty ratio control of the direction and the amperage of the current that flowsto the throttle control motor in order to regulate the opening of the throttle valve.

65ENGINE - 2UZ-FE ENGINE4) Magnetic CrutchOrdinarily, the magnetic clutch engages the clutch to enable the throttle control motor to open and closethe throttle valve. In case that a malfunction occurs in the system, this clutch is disengaged to preventthe throttle control motor to open and close the throttle valve.Operation1) GeneralThe ECM drives the throttle control motor by determining the target throttle valve opening in accordancewith the respective operating condition.1) Non-Linear Control2) Idle Speed Control3) TRAC Throttle Control4) VSC Coordination Control5) Cruise Control2) Non-Linear ControlControls the throttle to an optimal throttle valve opening that is appropriate for the driving condition suchas the amount of the accelerator pedal effort and the engine speed in order to realize excellent throttlecontrol and comfort in all operating ranges. Control Examples During Acceleration and Deceleration : With Control: No Control Vehicle’sLongitudinal G0 Throttle ValveOpening Angle0 Ignition Timing0Time 150EG373) Idle Speed ControlPreviously, a step motor type IAC valve was used to perform idle speed control such as fast idle duringcold operating conditions and idle-up. In conjunction with the adoption of the ETCS-i, controls the ECMand the throttle valve in order to constantly effect ideal idle speed control.

66ENGINE - 2UZ-FE ENGINE4) TRAC Throttle ControlAs part of the TRAC system, the throttle valve is closed by a demand signal from the skid control ECUif an excessive amount of slippage is created at a driving wheel, thus facilitating the vehicle in ensuringstability and driving force.5) VSC Coordination ControlIn order to bring the effectiveness of the VSC system control into full play, the throttle valve openingangle is controlled by effecting a coordination control with the skid control ECU.6) Cruise ControlPreviously the vehicle speed was controlled by the cruise control ECU, which open and closed the throttlevalve. In conjunction with the adoption of the ETCS-i, an ECM with an integrated cruise control ECUdiretly actuates the throttle valve to effect the operation.Fail-SafeIf an abnormal condition occurs with the ETCS-i, the MIL illuminates to alert the driver. At the same time,the current to the throttle control motor and magnetic clutch are cut off in order not to operate the ETCS-i.This enables the return spring to close the throttle valve.Even in this situation, the accelerator pedal can be used to operate the limp mode lever, which operates thethrottle valve to enable the vehicle to be driven in the limp mode.OpenLimp Mode LeverThrottle Position SensorThrottle Control MotorAcceleratorPedal agnosisThe diagnostic trouble codes can be output via DLC3 to an OBD-II scan tool or a hand-held tester. For details, refer to the 2001 Sequoia Repair Manual (Pub. No. RM832U).

68ENGINE - 2UZ-FE ENGINE8. Evaporative Emission Control SystemGeneralThe vacuum type has been adopted to detect leaks in the evaporative emission control system. This vacuumtype detects leaks by forcefully introducing the purge vacuum into the entire system and monitoring thechanges in the pressure. It consists of the following main components: A VSV (for canister closed valve) that closes the fresh air line from the air cleaner to the charcoal canisterhas been adopted. A VSV (for pressure switching valve) that opens the evaporator line between the fuel tank and the charcoal canister has been adopted. Function to close the purge line from the air intake chamber to the charcoal canister for this system isadded to the original functions of VSV (for EVAP). A vapor pressure sensor that measures the pressure in the fuel tank while checking for evaporative emission leaks and sends signals to the ECM has been adopted.Tank Pressure ValveVacuum Check ValveTank PressureValve AssemblyCharcoal CanisterVapor PressureSensorTo Intake ManifoldVSV(for Pressure Switching Valve)VSV(for EVAP)PressureSwitchingValveFrom AirCleanerVSVfor CanisterClosed ValvePurge ValveService PortCanisterClosed ValvePurge LineFresh Air LineAir Drain ValveAir Inlet ValveAir Valve Assembly196EG12

69ENGINE - 2UZ-FE ENGINEOperation1) Purge FlowWhen the engine has reached predetermined parameters (closed loop, engine coolant temp. above 74 C(165 F), etc.) stored fuel vapors are purged from the charcoal canister whenever the purge valve isopened by the ECM. At the appropriate time, the ECM will turn on the VSV (for EVAP).The ECM will change the duty ratio cycle of the VSV (for EVAP) thus controlling purge flow volume.Purge flow volume is determined by intake manifold pressure and the duty ratio cycle of the VSV (forEVAP). Atmospheric pressure is allowed into the charcoal canister to ensure that purge flow is constantlymaintained whenever purge vacuum is applied to the charcoal canister.CloseTo Intake ManifoldOpenFrom Air CleanerCloseOpenCloseOpen196EG13

70ENGINE - 2UZ-FE ENGINE2) MonitorThe monitor sequence begins with a cold engine start. The intake air temp. and engine coolant temp. sensors must have approximately the same temperature reading. The ECM is constantly monitoring fuel tankpressure. As the temperature of the fuel increases, pressure slowly rises. The ECM will purge the charcoalcanister at the appropriate time. With pressure switching valve closed, pressure will continue to rise infuel tank.CloseTo Intake ManifoldOpenCloseFrom Air loseOpenCloseOpenOpenCloseCloseNormal VaporPressureCold StartEngine Coolant/IntakeAir Near Same Temp.NegativePressureOccursFuel Tank &Charcoal CanisterLeak CheckAbnormalVaporPressureVSV (for Canister ClosedValve), VSV (for PressureSwitching Valve) Testing189EG33

71ENGINE - 2UZ-FE ENGINE3) DTC P0440 (Evaporative Emission Control System Malfunction)Initially when the canister

For details, refer to the 2001 Sequoia Repair Manual (Pub. No. RM832U).-56 ENGINE - 2UZ-FE ENGINE ENGINE CONTROL SYSTEM 1. General . The engine control system of the Sequoia’s 2UZ-FE engine and ’00 TOYOTA Tundra’s 2UZ-FE engine are compared below. System Outline ’01 Sequoia ’00 Toyota Tundra SFI