catalytic converter TOYOTA T100 1996 Factory Service Manual

Downloaded from www.Manualslib.com manuals search engine − INTRODUCTIONFOR ALL OF VEHICLES
IN−13
13 Author: Date:
1996 TOYOTA T100 (RM449U)
(f) CENTER AIRBAG SENSOR ASSEMBLY
(1) Never reuse the center airbag sensor assembly in-
volved in a collision when the SRS has deployed.
(2) The connectors to the center airbag sensor assem-
bly should be connected or disconnected with the
sensor mounted on the floor. If the connectors are
connected or disconnected while the center airbag
sensor assembly is not mounted to the floor, it could
cause undesired ignition of the supplemental re-
straint system.
(3) Work must be started after 90 seconds from the
time the ignition switch is turned to the ”LOCK” posi-
tion and the negative (−) terminal cable is discon-
nected from the battery, even if only loosening the
set bolts of the center airbag sensor assembly.
(g) WIRE HARNESS AND CONNECTOR
The SRS wire harness is integrated with the cowl wire har-
ness assembly and floor wire harness assembly. The
wires for the SRS wire harness are encased in a yellow
corrugated tube. All the connectors for the system are
also a standard yellow color. If the SRS wire harness be-
comes disconnected or the connector becomes broken
due to an accident, etc., repair or replace it.
2. FOR VEHICLES EQUIPPED WITH A CATALYTIC CONVERTER
CAUTION:
If 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 and prolonged braking.
(g) Do not dispose of used catalyst along with parts contaminated with gasoline or oil.

Downloaded from www.Manualslib.com manuals search engine IN−34
− INTRODUCTIONTERMS
1996 TOYOTA T100 (RM449U) HO2S
Heated Oxygen SensorHeated Oxygen Sensor (HO2S)
IACIdle Air ControlIdle Speed Control (ISC)
IATIntake Air TemperatureIntake or Inlet Air Temperature
ICMIgnition Control Module−
IFIIndirect Fuel InjectionIndirect Injection
IFSInertia Fuel−Shutoff−
ISCIdle Speed Control−
KSKnock SensorKnock Sensor
MAFMass Air FlowAir 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 Light
MSTManifold Surface Temperature−
MVZManifold Vacuum Zone−
NVRAMNon−Volatile Random Access Memory−
O2SOxygen SensorOxygen Sensor, O2 Sensor (O2S)
OBDOn−Board DiagnosticOn−Board Diagnostic (OBD)
OCOxidation Catalytic ConverterOxidation Catalyst Converter (OC), CCo
OPOpen 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 Bypass−
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

Downloaded from www.Manualslib.com manuals search engine − INTRODUCTIONTERMS
IN−35
1996 TOYOTA T100 (RM449U) TCM
Transmission Control ModuleTransmission ECU (Electronic Control Unit)
TPThrottle PositionThrottle Position
TRTransmission Range−
TVVThermal Vacuum ValveBimetallic Vacuum Switching Valve (BVSV)
Thermostatic Vacuum Switching Valve (TVSV)
TWCThree−Way Catalytic ConverterThree−Way Catalytic (TWC)
CC
RO
TWC+OCThree−Way + Oxidation Catalytic ConverterCCR + CCo
VA FVolume Air FlowAir Flow Meter
VRVoltage RegulatorVoltage Regulator
VSSVehicle Speed SensorVehicle Speed Sensor (Read Switch Type)
WOTWide Open ThrottleFull Throttle
WU−OCWarm Up Oxidation Catalytic Converter−
WU−TWCWarm Up Three−Way Catalytic ConverterManifold Converter
3GRThird Gear−
4GRFourth Gear−

Downloaded from www.Manualslib.com manuals search engine P21242 FI7210
A00027
Atmosphere
Flange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust GasCoverIdeal Air−Fuel Mixture
Output Voltage
Richer − Air Fuel Ratio − Leaner DI−44
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three−way
catalytic 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 oxygen sensor has the characteristic where by its output voltage changes suddenly in the vicinity of the
stoichiometric air−fuel ratio. This is used to detect the oxygen concentration in the exhaust gas and provide
feedback to the computer for control of the air−fuel ratio.
When the air−fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the oxygen
sensor informs the ECM of the LEAN condition (small electromotive force: 0 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 oxygen sensor informs the ECM of the RICH condition (large electromotive
force: 1 V). The ECM judges by the electromotive force from the oxygen sensor whether the air−fuel ratio
is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the oxygen sensor
causes output of abnormal electromotive force, the ECM is unable to perform 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 temp. of the exhaust gas is low) current flows to the heater
to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After engine is warmed up, heated oxygen sensor output
does not indicate RICH even once when conditions (a), (b),
(c) and (d) continue for at least 1.5 min.:
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 ∼ 100 km/h (25 ∼ 62 mph)
(c) Closed throttle position switch: OFF
(d) 140 sec. or more after starting engine
Open or short in heated oxygen sensor (bank 1 sensor 1)
circuit
Heated oxygen sensor (bank 1 sensor 1)
HINT:
After confirming DTC P0125 use the OBD II scan tool or TOYOTA handheld tester to confirm voltage output
of heated oxygen sensor from "CURRENT DATA".
If voltage output of heated oxygen sensor is 0 V, heated oxygen sensor circuit may be open or short.
DI0TJ−02

Downloaded from www.Manualslib.com manuals search engine FI7081
Waveform of Oxygen Sensor
before CatalystNormal CatalystWaveform of Oxygen Sensor
after Catalyst
P25762
Engine Speed
2500 − 3000 rpm
Idling
IG SW OFF
Warmed up3 minutesCheckTime (1)(3)
(4)
(2) DI−86
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0420 Catalyst System Efficiency Below Threshold
CIRCUIT DESCRIPTION
The ECM compares the waveform of the oxygen sensor located before the catalyst with the waveform of
the oxygen sensor located after the catalyst to determine whether or not catalyst performance has deterio-
rated.
Air−fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeat-
edly changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back
and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the cata-
lyst.
But when both waveforms change at a similar rate, it indicates that catalyst performance has deteriorated.


DTC No.DTC Detecting ConditionTrouble Area
P0420
After engine and catalyst are warmed up, and while vehicle is
driven within set vehicle and engine speed range, waveforms
of heated oxygen sensors (bank 1 sensor 1, 2) have same
amplitude (2 trip detection logic)
TWC (Three−way catalytic converter)
Heated oxygen sensor (bank 1 sensor 1, 2)
CONFIRMATION ENGINE RACING PATTERN
DI0TW−02

Downloaded from www.Manualslib.com manuals search engine − DIAGNOSTICSENGINE (5VZ−FE)
DI−141
1996 TOYOTA T100 (RM449U) DTC No.
(See Page)
Detection ItemTrouble AreaMILMemory
P0171
(DI−180)System too Lean
(Fuel Trim)
Air intake (hose loose)
Fuel line pressure
Injector blockage
Heated oxygen sensor (bank 1 sensor 1) malfunction
Mass air flow meter
Engine coolant temp. sensor
*1
P0172
(DI−180)System too Rich
(Fuel Trim)
Fuel line pressure
Injector leak, blockage
Heated oxygen sensor (bank 1 sensor 1) malfunction
Mass air flow meter
Engine coolant temp. sensor
*1
P0300
(DI−183)Random/Multiple Cylinder
Misfire DetectedIgnition system
Injector
Fuel line pressure
EGR*3
Compression pressure
Valve clearance not to specification
Valve timing
Mass air flow meter
Engine coolant temp. sensor*2
P0301
P0302
P0303
P0304
P0305
P0306
(DI−183)Misfire Detected
− Cylinder 1
− Cylinder 2
− Cylinder 3
− Cylinder 4
− Cylinder 5
− Cylinder 6
*2
P0325
(DI−188)Knock Sensor 1 Circuit
MalfunctionOpen or short in knock sensor 1 circuit
Knock sensor 1 (looseness)
ECM
*1
P0330
(DI−188)Knock Sensor 2 Circuit
MalfunctionOpen or short in knock sensor 2 circuit
Knock sensor 2 (looseness)
ECM
*1
P0335
(DI−191)Crankshaft Position Sensor
”A” Circuit Malfunction
Open or short in crankshaft position sensor circuit
Crankshaft position sensor
Starter
ECM
*1 
P0340
(DI−194)Camshaft Position Sensor
Circuit Malfunction
Open or short in camshaft position sensor circuit
Camshaft position sensor
Starter
ECM
*1 
P0401*3
(DI−196)Exhaust Gas Recirculation
Flow Insufficient Detected
EGR valve stuck closed
Short in VSV circuit for EGR
Open in EGR gas temp. sensor circuit
EGR hose disconnected
ECM
*1 
P0402*3
(DI−206)Exhaust Gas Recirculation
Flow Excessive Detected
EGR valve stuck open
EGR VSV open malfunction
Open in VSV circuit for EGR
Short in EGR gas temp. sensor circuit
ECM
*1
P0420
(DI−210)Catalyst System Efficiency
Below Threshold
Three−way catalytic converter
Open or short in heated oxygen sensor (bank 1 sensor 1, 2)
circuit
Heated oxygen sensor (bank 1 sensor 1, 2)
*1
*1: MIL lights up
*2: MIL lights up or blinking
*3: Only for 2WD models with a load capacity of 0.5 ton and regular cab.

Downloaded from www.Manualslib.com manuals search engine P21242 FI7210
A00027
Atomosphere
CoverIdeal Air−Fuel Mixture
Exhaust GasFlange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating(Ceramic)
Output Voltage
Richer  Air−fuel Ratio  Leaner
− DIAGNOSTICSENGINE (5VZ−FE)
DI−169
1996 TOYOTA T100 (RM449U)
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three−way
catalytic 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 oxygen sensor has the characteristic whereby 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 exhaust
gas and provide feedback to the computer for control of the air−fuel ratio.
When the air−fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the oxygen
sensor informs the ECM of the LEAN condition (small electromotive force: 0 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 oxygen sensor informs the ECM of the RICH condition (large electromotive
force: 1 V). The ECM judges by the electromotive force from the oxygen sensor whether the air−fuel ratio
is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the oxygen sensor
causes output of abnormal electromotive force, the ECM is unable to perform 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 temp. of the exhaust gas is low) current flows to the heater
to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After engine is warmed up, heated oxygen sensor output
does not indicate RICH even once when conditions (a), (b),
(c) and (d) continue for at least 1.5 min.:
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 − 100 km/h (25 − 62 mph)
(c) Throttle valve does not fully closed
(d) 140 sec. or more after starting engine
Open or short in heated oxygen sensor
(bank1 sensor 1) circuit
Heated oxygen sensor (bank 1 sensor 1)
DI0UN−01

Downloaded from www.Manualslib.com manuals search engine FI7081
Waveform of Oxygen Sensor
before CatalystNormal Catalyst Waveform of Oxygen Sensor
after Catalyst
P25762
Engine Speed
2500 − 3000 rpm
Idling
IG SW OFF
Warmed up 3 minutes CheckTime (1)(3)
(4)
(2) DI−210
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0420 Catalyst System Efficiency Below Threshold
CIRCUIT DESCRIPTION
The ECM compares the waveform of the oxygen sensor located before the catalyst with the waveform of
the oxygen sensor located after the catalyst to determine whether or not catalyst performance has deterio-
rated.
Air−fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeat-
edly changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back
and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the cata-
lyst.
But when both waveforms change at a similar rate, it indicates that catalyst performance has deteriorated.


DTC No.DTC Detecting ConditionTrouble Area
P0420
After engine and catalyst are warmed up, and while
vehicle is driven within set vehicle and engine speed range,
waveforms of heated oxygen sensors (bank 1 sensor 1, 2)
have same amplitude
(2 trip detection logic)Three−way catalytic converter
Open or short in heated oxygen sensor (bank 1 sensor 1, 2)
circuit
Heated oxygen sensor (bank 1 sensor 1, 2)
CONFIRMATION ENGINE RACING PATTERN
DI0UZ−01

Downloaded from www.Manualslib.com manuals search engine EC – EMISSIONS CONTROL (3RZ-FE)

EMISSION CONTROL SYSTEM EC-1
PARTS LAYOUT AND SCHEMATIC
DRAWING EC-2
POSITIVE CRANKCASE VENTILATION
(PCV) SYSTEM EC-4
EVAPORATIVE EMISSION (EVAP)
CONTROL SYSTEM EC-5
EXHAUST GAS RECIRCULATION
(EGR) SYSTEM EC-7
THREE-WAY CATALYTIC CONVERTER
(TWC) SYSTEM EC-10

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− EMISSION CONTROL (3RZ−FE)EMISSION CONTROL SYSTEM
EC−1
929 Author: Date:
1996 TOYOTA T100 (RM449U)
EMISSION CONTROL SYSTEM
PURPOSE
The emission control systems are installed to reduce the amount of CO, HC and NOx exhausted from the
engine ((3), (4) and (5)), to prevent the atmospheric release of blow−by gas−containing HC (1) and evapo-
rated fuel containing HC being released from the fuel tank (2).
The function of each system is shown in these table.
SystemAbbreviationFunction
(1) Positive Crankcase Ventilation
(2) Evaporative Emission Control
(3) Exhaust Gas Recirculation
(4) Three−Way Catalytic Converter
(5) Multiport Fuel Injection *PCV
EVAP
EGR
TWC
MFIReduces HC
Reduces evaporated HC
Reduces NOx
Reduces CO, HC and NOx
Injects a precisely timed, optimum amount of fuel for reduced exhaust
emissions
Remark: * For inspection and repair of the MFI system, refer to the MF section this manual.