catalytic TOYOTA SEQUOIA 2001 Service Repair Manual
[x] Cancel search | Manufacturer: TOYOTA, Model Year: 2001, Model line: SEQUOIA, Model: TOYOTA SEQUOIA 2001Pages: 4323, PDF Size: 48.49 MB
Page 18 of 4323
B04770
IN±18
± INTRODUCTIONFOR ALL OF VEHICLES
18 Author: Date:
2005 SEQUOIA (RM1146U)
(4) Check that the VSC TRAC warning light blinks.
(5) After the measurement, remove the SST and re-
start the engine. At this time, make sure that the
VSC TRAC warning light is off.
(b) Notice in VSC operation.
(1) Removal and reinstallation of VSC±related compo-
nents may cause misadjustment of them. Do not re-
move or reinstall them unless necessary.
(2) When conducting VSC±related operations, do not
fail to make sure that the preparation and the finish-
ing of the operation are all performed in accordance
with the direction in this text.
3. FOR VEHICLES EQUIPPED WITH A CATALYTIC CONVERTER
CAUTION:
If a large amount of unburned gasoline flows into the converter, it may overheat and create a fire haz-
ard. To prevent this, observe the following precautions and explain them to your customer.
(a) Use only unleaded gasoline.
(b) Avoid prolonged idling.
Avoid running the engine at idle speed for more than 20 minutes.
(c) Avoid spark jump test.
(1) Perform spark jump test only when absolutely necessary. Perform this test as rapidly as possible.
(2) While testing, never race the engine.
(d) Avoid prolonged engine compression measurement.
Engine compression tests must be done as rapidly as possible.
(e) Do not run engine when fuel tank is nearly empty.
This may cause the engine to misfire and create an extra load on the converter.
(f) Avoid coasting with ignition turned off.
(g) Do not dispose of used catalyst along with parts contaminated with gasoline or oil.
4. IF VEHICLE IS EQUIPPED WITH MOBILE COMMUNICATION SYSTEM
For vehicles with mobile communication systems such as two±way radios and cellular telephones, observe
the following precautions.
(1) Install the antenna as far as possible away from the ECU and sensors of the vehicle's electronic
system.
(2) Install the antenna feeder at least 20 cm (7.87 in.) away from the ECU and sensors of the ve-
hicle's electronic systems. For details about ECU and sensor locations, refer to the section on
the applicable component.
(3) Do not wind the antenna feeder together with the other wiring as much as possible, also avoid
running the antenna feeder parallel with other wire harness.
(4) Check that the antenna and feeder are correctly adjusted.
(5) Do not install powerful mobile communication system.
Page 40 of 4323
IN04Q±33
IN±40
± INTRODUCTIONTERMS
40 Author: Date:
2005 SEQUOIA (RM1146U)
TERMS
ABBREVIATIONS USED IN THIS MANUAL
AbbreviationsMeaning
ABSAnti±Lock Brake System
A/CAir Conditioner
ACAlternating Current
ACCAccessory
ACISAcoustic Control Induction System
ACMActive Control Engine Mount
ACSDAutomatic Cold Start Device
A.D.D.Automatic Disconnecting Differential
A/FAir±Fuel Ratio
AHCActive Height Control Suspension
ALRAutomatic Locking Retractor
ALTAlternator
AMPAmplifier
ANTAntenna
APPROX.Approximately
ASSYAssembly
A/T, ATMAutomatic Transmission (Transaxle)
AT FAutomatic Transmission Fluid
AUTOAutomatic
AUXAuxiliary
AV GAverage
AV SAdaptive Variable Suspension
B+Battery Voltage
BABrake Assist
BACSBoost Altitude Compensation System
BATBattery
BDCBottom Dead Center
B/LBi±Level
B/SBore±Stroke Ratio
BTDCBefore Top Dead Center
BVSVBimetallic Vacuum Switching Valve
CBCircuit Breaker
CCoCatalytic Converter For Oxidation
CCVCanister Closed Valve
CDCompact Disc
CFCornering Force
CGCenter Of Gravity
CHChannel
CKDComplete Knock Down
COMB.Combination
CPECoupe
CPSCombustion Pressure Sensor
CPUCentral Processing Unit
CRSChild Restraint System
CTRCenter
C/VCheck Valve
CVControl Valve
CWCurb Weight
Page 46 of 4323
IN±46
± INTRODUCTIONTERMS
46 Author: Date:
2005 SEQUOIA (RM1146U) IAC
Idle Air ControlIdle Speed Control (ISC)
IATIntake Air TemperatureIntake or Inlet Air Temperature
ICMIgnition Control Module±
IFIIndirect Fuel InjectionIndirect Injection (IDL)
IFSInertia Fuel±Shutoff±
ISCIdle Speed Control±
KSKnock SensorKnock Sensor
MAFMass AirflowAir Flow Meter
MAPManifold Absolute PressureManifold Pressure Intake Vacuum
MCMixture Control
Electric Bleed Air Control Valve (EBCV)
Mixture Control Valve (MCV)
Electric Air Control Valve (EACV)
MDPManifold Differential Pressure±
MFIMultiport Fuel InjectionElectronic Fuel Injection (EFI)
MILMalfunction Indicator LampCheck Engine Lamp
MSTManifold Surface Temperature±
MVZManifold Vacuum Zone±
NVRAMNon±Volatile Random Access Memory±
O2SOxygen SensorOxygen Sensor, O2 Sensor (O2S)
OBDOn±Board DiagnosticOn±Board Diagnostic System (OBD)
OCOxidation Catalytic ConverterOxidation Catalyst Convert (OC), CCo
OLOpen LoopOpen Loop
PAIRPulsed Secondary Air InjectionAir Suction (AS)
PCMPowertrain Control Module±
PNPPark/Neutral Position±
PROMProgrammable Read Only Memory±
PSPPower Steering Pressure±
PTOXPeriodic Trap OxidizerDiesel Particulate Filter (DPF)
Diesel Particulate Trap (DPT)
RAMRandom Access MemoryRandom Access Memory (RAM)
RMRelay Module±
ROMRead Only MemoryRead Only Memory (ROM)
RPMEngine SpeedEngine Speed
SCSuperchargerSupercharger
SCBSupercharger BypassE±ABV
SFISequential Multiport Fuel InjectionElectronic Fuel Injection (EFI), Sequential Injection
SPLSmoke Puff Limiter±
SRIService Reminder Indicator±
SRTSystem Readiness Test±
STScan Tool±
TBThrottle BodyThrottle Body
TBIThrottle Body Fuel InjectionSingle Point Injection
Central Fuel Injection (Ci)
TCTurbochargerTurbocharger
TCCTorque Converter ClutchTorque Converter
TCMTransmission Control ModuleTransmission ECU, ECT ECU
Page 47 of 4323
± INTRODUCTIONTERMS
IN±47
47 Author: Date:
2005 SEQUOIA (RM1146U) TP
Throttle PositionThrottle Position
TRTransmission Range±
TVVThermal Vacuum ValveBimetallic Vacuum Switching Valve (BVSV)
Thermostatic Vacuum Switching Valve (TVSV)
TWCThree±Way Catalytic Converter
Three±Way Catalytic (TWC)
Manifold Converter
CC
RO
TWC+OCThree±Way + Oxidation Catalytic ConverterCCR + CCo
VA FVolume AirflowAir Flow Meter
VRVoltage RegulatorVoltage Regulator
VSSVehicle Speed SensorVehicle Speed Sensor
WOTWide Open ThrottleFull Throttle
WU±OCWarm Up Oxidation Catalytic Converter±
WU±TWCWarm Up Three±Way Catalytic Converter±
3GRThird Gear±
4GRFourth Gear±
Page 197 of 4323
DID7O±02
± DIAGNOSTICSENGINE
DI±3
197 Author: Date:
2005 SEQUOIA (RM1146U)
TOYOTA PART AND SYSTEM NAME LIST
This reference list indicates the part names used in this manual along with their definitions.
TOYOTA/LEXUS nameDefinition
Toyota HCAC system, Hydro±carbon Adsorptive Catalyst
(HCAC) system, HC adsorptive three±way catalystHC adsorptive three±way catalytic converter
Variable Valve Timing sensor, VVT sensorCamshaft position sensor
Variable valve timing system, VVT systemCamshaft timing control system
Camshaft timing oil control valve, Oil control valve, OCV,
VVT, VSVCamshaft timing oil control valve
Variable timing and lift, VVTLCamshaft timing and lift control
Crankshaft position sensor ºAºCrankshaft position sensor
Engine speed sensorCrankshaft position sensor
THAIntake air temperature
Knock control moduleEngine knock control module
Knock sensorEngine knock sensor
Mass or volume air flow circuitMass air flow sensor circuit
Vacuum sensorManifold air pressure sensor
Internal control module, Control module, Engine control
ECU, PCMPower train control module
FC idleDeceleration fuel cut
Idle air control valveIdle speed control
VSV for CCV, Canister close valve VSV for canister controlEvaporative emissions canister vent valve
VSV for EVAP, Vacuum switching valve assembly No. 1,
EVAP VSV, Purge VSVEvaporative emissions canister purge valve
VSV for pressure switching valve, Bypass VSVEvaporative emission pressure switching valve
Vapor pressure sensor, EVAP pressure sensor, Evaporative
emission control system pressure sensorFuel tank pressure sensor
Charcoal canisterEvaporative emissions canister
ORVR systemOn±board refueling vapor recovery system
Intake manifold runner controlIntake manifold tuning system
Intake manifold runner valve, IMRV, IACV (runner valve)Intake manifold tuning valve
Intake control VSVIntake manifold tuning solenoid valve
AFSAir fuel ratio sensor
O2 sensorHeater oxygen sensor
Oxygen sensor pumping current circuitOxygen sensor output signal
Oxygen sensor reference ground circuitOxygen sensor signal ground
Accel position sensorAccelerator pedal position sensor
Throttle actuator control motor, Actuator control motor, Elec-
tronic throttle motor, Throttle control motorElectronic throttle actuator
Electronic throttle control system, Throttle actuator control
systemElectronic throttle control system
Throttle/pedal position sensor, Throttle/pedal position switch,
Throttle position sensor/switchThrottle position sensor
Turbo press sensorTurbocharger pressure sensor
Turbo VSVTurbocharger pressure control solenoid valve
P/S pressure switchPower±steering pressure switch
VSV for ACMActive control engine mount
Page 259 of 4323
± DIAGNOSTICSENGINE
DI±65
259 Author: Date:
2005 SEQUOIA (RM1146U)P0351
(DI±221)
Ignition Coil ºAº Primary/Second-
ary Circuit
Open or short in IGF 1 and IGT 1 circuit from No. 1 ignition coil
with igniter to ECM
No. 1 ignition coil with igniter
Ignition system
ECM
P0352
(DI±221)Ignition Coil ºBº Primary/Second-
ary Circuit
Open or short in IGF 2 and IGT 2 circuit from No. 2 ignition coil
with igniter to ECM
No. 2 ignition coil with igniter
Ignition system
ECM
P0353
(DI±221)Ignition Coil ºCº Primary/Second-
ary Circuit
Open or short in IGF 2 and IGT 3 circuit from No. 3 ignition
coil with igniter to ECM
No. 3 ignition coil with igniter
Ignition system
ECM
P0354
(DI±221)Ignition Coil ºDº Primary/Second-
ary Circuit
Open or short in IGF 1 and IGT 4 circuit from No. 4 ignition coil
with igniter to ECM
No. 4 ignition coil with igniter
Ignition system
ECM
P0355
(DI±221)Ignition Coil ºEº Primary/Second-
ary Circuit
Open or short in IGF 2 and IGT 5 circuit from No. 5 ignition coil
with igniter to ECM
No. 5 ignition coil with igniter
Ignition system
ECM
P0356
(DI±221)Ignition Coil ºFº Primary/Second-
ary Circuit
Open or short in IGF 1 and IGT 6 circuit from No. 6 ignition coil
with igniter to ECM
No. 6 ignition coil with igniter
Ignition system
ECM
P0357
(DI±221)Ignition Coil ºGº Primary/Second-
ary Circuit
Open or short in IGF 1 and IGT 7 circuit from No. 7 ignition coil
with igniter to ECM
No. 7 ignition coil with igniter
Ignition system
ECM
P0358
(DI±221)Ignition Coil ºHº Primary/Second-
ary Circuit
Open or short in IGF 2 and IGT 8 circuit from No. 8 ignition coil
with igniter to ECM
No. 8 ignition coil with igniter
Ignition system
ECM
P0412
(DI±234)Air Injection System Air Switch-
ing Valve Malfunction
Open in air switching valve drive circuit
Short between air switching valve circuit and +B circuit
Air injection driver
ECM
P0418
(DI±242)Air Injection System Air Pump
Malfunction
Open in air pump drive circuit
Short between air pump circuit and +B circuit
Air injection driver
ECM
P0420
(DI±249)Catalyst System Efficiency Be-
low Threshold (Bank 1)Gas leakage on exhaust system
Heated oxygen sensor (bank 1 sensor 1, 2)
Three±way catalytic converter
P0430
(DI±249)Catalyst System Efficiency Be-
low Threshold (Bank 2)Gas leakage on exhaust system
Heated oxygen sensor (bank 2 sensor 1, 2)
Three±way catalytic converter
Page 283 of 4323
± DIAGNOSTICSENGINE
DI±89
283 Author: Date:
2005 SEQUOIA (RM1146U)
HINT:
Bank 1 refers to the bank that includes cylinder No.1.
Bank 2 refers to the bank that does not include cylinder No.1.
Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
MONITOR DESCRIPTION
The ECM uses the Air±Fuel Ratio sensor (A/F sensor) information to regulate the air±fuel ratio close to the
stoichiometric ratio. This maximizes the catalytic converter's ability to purify exhaust gases. The sensor de-
tects oxygen levels in the exhaust gas and sends this signal to the ECM.
The inner surface of the sensor element is exposed to outside air. The outer surface of the sensor element
is exposed to exhaust gas. The sensor element is made of platinum coated zirconia and includes an inte-
grated heating element. The zirconia element generates a small voltage when there is a large difference in
the oxygen concentrations of the exhaust and the outside air. The platinum coating amplifies the voltage
generation. When heated, the sensor becomes very efficient. If the temperature of the exhaust is low, the
sensor will not generate useful voltage signals without supplemental heating. The ECM regulates the sup-
plemental heating using a duty±cycle approach to regulate the average current in the heater element. If the
heater current is out of the normal range, the sensor's output signals will be inaccurate and the ECM can
not regulate the air±fuel ratio properly.
When the heater current is out of the normal operating range, the ECM interprets this as a malfunction and
sets a DTC.
MONITOR STRATEGY
P0031A/F sensor heater (Bank 1) range check (Low
current)
RltdDTC
P0032A/F sensor heater (Bank 1) range check (High
current)
Related DTCs
P0051A/F sensor heater (Bank 2) range check (Low
current)
P0052A/F sensor heater (Bank 2) range check (High
current)
Rid / tMain sensors/componentsA/F sensor heaterRequired sensors/componentsRelated sensors/components±
Frequency of operationContinuous
Duration10 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
P0031, P0051 (Low current):
Battery voltage10.5 V±
A/F sensor heater duty ratio50%±
Time after engine start10 sec.±
Page 288 of 4323
B17386
Housing
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust Gas CoverIdeal Air±Fuel Mixture
Output Voltage
Richer ± Air Fuel Ratio ± Leaner
Atmospheric Air
A21040
Reference(Bank 1 Sensor 1 System Drawing) :
ECM
EFI Relay
EFI Fuse No. 1 From
Battery
GroundOX1A
MREL HT1A
Duty
Control Heater
Sensor Heated Oxygen Sensor
EFI Fuse No. 2
E2 DI±94
± DIAGNOSTICSENGINE
288 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three±way cata-
lytic converter is used, but for the most efficient use of the three±way catalytic converter, the air±fuel ratio
must be precisely controlled so that it is always close to the stoichiometric air±fuel ratio.
The heated oxygen sensor has the characteristic which its output voltage changes suddenly in the vicinity
of the stoichiometric air±fuel ratio. This characteristic is used to detect the oxygen concentration in the ex-
haust gas and provide the ECM with feedback to control the air±fuel ratio.
When the air±fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the heated
oxygen sensor informs the ECM of the LEAN condition (low voltage, i.e. less than 0.45 V).
When the air±fuel ratio is RICHER than the stoichiometric air±fuel ratio, the oxygen concentration in the ex-
haust gas is reduced and the heated oxygen sensor informs the ECM of the RICH condition (high voltage,
i.e. more than 0.45 V). The ECM judges by the voltage output from the heated oxygen sensor whether the
air±fuel ratio is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the
heated oxygen sensor causes output of abnormal voltage, this disables the ECM for performing an accurate
air±fuel ratio control. The heated oxygen sensors include a heater which heats the zirconia element. The
heater is controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is
low) current flows to the heater to heat the sensor for accurate oxygen concentration detection.
HINT:
The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated
oxygen sensor heater circuit uses a relay on the B+ side of the circuit.
Page 340 of 4323
DI±146
± DIAGNOSTICSENGINE
340 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1
Sensor 2)
DTC P0137 Oxygen Sensor Circuit Low Voltage (Bank 1
Sensor 2)
DTC P0138 Oxygen Sensor Circuit High Voltage (Bank 1
Sensor 2)
DTC P0156 Oxygen Sensor Circuit Malfunction (Bank 2
Sensor 2)
DTC P0157 Oxygen Sensor Circuit Low Voltage (Bank 2
Sensor 2)
DTC P0158 Oxygen Sensor Circuit High Voltage (Bank 2
Sensor 2)
HINT:
Sensor 2 refers to the sensor mounted behind the Three±Way Catalytic Converter (TWC) and located far
from the engine assembly.
CIRCUIT DESCRIPTION
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide
(NOx) components in the exhaust gas, a TWC is used. For the most efficient use of the TWC, the air±fuel
ratio must be precisely controlled so that it is always close to the stoichiometric air±fuel level. For the purpose
of helping the ECM to deliver accurate air±fuel ratio control, a Heated Oxygen (HO2) sensor is used.
The HO2 sensor is located behind the TWC, and detects the oxygen concentration in the exhaust gas. Since
the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen
concentration even when the intake air volume is low (the exhaust gas temperature is low).
When the air±fuel ratio becomes lean, the oxygen concentration in the exhaust gas is rich. The HO2 sensor
informs the ECM that the post±TWC air±fuel ratio is lean (low voltage, i.e. less than 0.45 V).
Conversely, when the air±fuel ratio is richer than the stoichiometric air±fuel level, the oxygen concentration
in the exhaust gas becomes lean. The HO2 sensor informs the ECM that the post±TWC air±fuel ratio is rich
(high voltage, i.e. more than 0.45 V). The HO2 sensor has the property of changing its output voltage drasti-
cally when the air±fuel ratio is close to the stoichiometric level.
The ECM uses the supplementary information from the HO2 sensor to determine whether the air±fuel ratio
after the TWC is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the HO2 sensor is work-
DIDFR±01
Page 342 of 4323
B17387
Active air±fuel
ratio control
OffOperation15 to 20 seconds
HO2 sensor
voltage
Abnormal Normal
0.21 V 0.59 V HO2 SENSOR CIRCUIT MALFUNCTION (P0136, P0156: ABNORMAL VOLTAGE) DI±148
± DIAGNOSTICSENGINE
342 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
Active Air±Fuel Ratio Control
The ECM usually performs air±fuel ratio feedback control so that the Air±Fuel Ratio (A/F) sensor output indi-
cates a near stoichiometric air±fuel level. This vehicle includes active air±fuel ratio control in addition to regu-
lar air±fuel ratio control. The ECM performs active air±fuel ratio control to detect any deterioration in the
Three±Way Catalytic Converter (TWC) and Heated Oxygen (HO2) sensor malfunctions (refer to the diagram
below).
Active air±fuel ratio control is performed for approximately 15 to 20 seconds while driving with a warm engine.
During active air±fuel ratio control, the air±fuel ratio is forcibly regulated to become lean or rich by the ECM.
If the ECM detects a malfunction, one of the following DTCs is set: DTC P0136, P0156 (abnormal voltage
output), P0137, P0157 (open circuit) and P0138, P0158 (short circuit).
Abnormal Voltage Output of HO2 Sensor (DTC P0136, P0156)
While the ECM is performing active air±fuel ratio control, the air±fuel ratio is forcibly regulated to become
rich or lean. If the sensor is not functioning properly, the voltage output variation is small. For example, when
the HO2 sensor voltage does not decrease to less than 0.21 V and does not increase to more than 0.59 V
during active air±fuel ratio control, the ECM determines that the sensor voltage output is abnormal and sets
DTC P0136.