1997 TOYOTA SUPRA catalytic converter

IN-14
- INTRODUCTIONFOR ALL OF VEHICLES
14 Author
: Date
:
1997 SUPRA (RM502U)
(f) AIRBAG SENSOR ASSEMBLY
(1) Never reuse the airbag sensor assembly involved
in a collision when the SRS has deployed.
(2) The connectors to the airbag sensor assembly
should be connected or disconnected with the sen-
sor mounted on the floor. If the connectors are con-
nected or disconnected while the airbag sensor as-
sembly is not mounted to the floor, it could cause
undesired ignition of the supplemental restraint sys-
tem.
(3) Work must be started after 90 seconds from the
time the ignition switch is turned to the ºLOCKº posi-
tion and the negative (-) terminal cable is discon-
nected from the battery, even if only loosening the
set bolts of the 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 as shown on
page RS-38.
2. FOR VEHICLES EQUIPPED WITH A CATALYTIC CONVERTER
If large amounts of unburned gasoline flow into the converter, it may overheat and create a fire hazard. 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.
3. IF VEHICLE IS EQUIPPED WITH MOBILE COMMUNICATION SYSTEM
(a) For vehicles with mobile communication systems such as two-way radios and cellular telephones, ob-
serve the following precautions.
(b) Install the antenna as far as possible away from the ECU and sensors of the vehicle's electronic sys-
tem.

IN-36
- INTRODUCTIONTERMS
36 Author
: Date
:
1997 SUPRA (RM502U) 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-V olatile 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

- INTRODUCTIONTERMS
IN-37
37 Author
: Date
:
1997 SUPRA (RM502U) 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-W ay Catalytic ConverterThree-W ay Catalytic (TWC)
CC
RO
TWC+OCThree-W ay + 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-

DI-160
- DIAGNOSTICSENGINE (2JZ-GTE)
388 Author
: Date
:
1997 SUPRA (RM502U)DTC No.
(See Page)
Detection ItemTrouble AreaMIL*Memory
P0340
(DI-215)Camshaft Position Sensor
Circuit Malfunction
Open or short in camshaft position sensor circuit
Camshaft position sensor
Open or short in crankshaft position sensor circuit for NE2
signal
Crankshaft position sensor for NE2 signal
Starter
ECM

P0401
(DI-217)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

P0402
(DI-227)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

P0420
(DI-231)Catalyst System Efficiency
Below ThresholdThree-way catalytic converter
Open or short in heated oxygen sensor circuit
Heated oxygen sensor

P0441
(DI-234)Evaporative Emission Control
System Incorrect Purge Flow
Open or short in VSV circuit for EVAP
VSV for EVAP
ECM
Vacuum hose blocked or disconnected
Charcoal canister

P0500
(DI-238)Vehicle Speed Sensor
Malfunction
Open or short in vehicle speed sensor circuit
Vehicle speed sensor
Combination meter
ECM

P0505
(DI-240)Idle Control System Malfunction
IAC valve is stuck or closed
Open or short in IAC valve circuit
Open or short in A/C signal circuit
Air intake (hose loose)

P0510
(DI-243)Closed Throttle Position Switch
MalfunctionOpen in closed throttle position switch circuit
Closed throttle position switch
ECM

*: ... MIL lights up

A00697
Cover
Atmosphere
Housing
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
HeaterPlatinum Electrode
Coating (Ceramic)
Output Voltage
Exhaust GasIdeal Air-Fuel Mixture
Richer - Air Fuel Ratio - Leaner DI-190
- DIAGNOSTICSENGINE (2JZ-GTE)
418 Author
: Date
:
1997 SUPRA (RM502U)
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 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 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 out-
put 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 temperature 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 the engine is warmed up, heated oxygen sensor output
does not indicate RICH even once when conditions (a), (b) and
(c) continue for at least 2 min. :
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 - 100 km/h (25 - 62 mph)
(c) Closed throttle position SW: OFF

Open or short in heated oxygen sensor circuit

Heated oxygen sensor
HINT:
After confirming DTC P0125 use the OBD II scan tool or TOYOTA hand-held tester to confirm voltage output
of heated oxygen sensor from ºCURRENT DATAº.
If voltage output of heated oxygen sensor is 0 V, heated oxygen sensor circuit may be open or short.
DI4ST-01

FI7081
Waveform of oxygen sensor
before catalystNormal
catalystWaveform of oxygen sensor
after catalyst
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-231
459 Author
: Date
:
1997 SUPRA (RM502U)
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 wavaforms change at a similar rate, it indicates that catalyst performance has deteriorated.
DTC No.DTC Detecting ConditionTrouble Area
P0420
After the engine and the catalyst are warmed up, and while the
vehicle is driven within the set vehicle and engine speed range,
the waveforms of the heated oxygen sensors (bank 1 sensor 1
and bank 1 sensor 2) have the same amplitude
(2 trip detection logic)

Three-way catalytic converter

Open or short in heated oxygen sensor circuit

Heated oxygen sensor
DI4T5-01

- DIAGNOSTICSENGINE (2JZ-GTE)
DI-233
461 Author
: Date
:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Are there any other code (besides DTC P0420) being output?
YES Go to relevant DTC chart.
NO
2 Check heated oxygen senor (bank 1, sensor 1) (See page DI-193).
NG Repair or replace.
OK
3 Check heated oxygen senor (bank1, sensor 2) (See page DI-199).
NG Repair or replace.
OK
Replace three-way catalytic converter.

EC042-01
- EMISSION CONTROL (2JZ-GTE)EMISSION CONTROL SYSTEM
EC-1
1238 Author
: Date
:
1997 SUPRA (RM502U)
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) Sequential Multiport Fuel Injection *PCV
EVAP
EGR
TWC
SFIReduces 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 SFI system, refer to the SFI section this manual.