1997 TOYOTA SUPRA fuel

FI4741
Acceptable
Resistance kW
-20 0
20 40 60 80 100
(-4) (32) (68)(104)(140)(176)(212)
Temperature °C (°F) 0.1 0.20.3 0.51 2 35 10 2030
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-175
403 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temperature sensor is built into the air flow meter
and senses the intake air temperature.
A thermistor built in the sensor changes the resistance value
according to the intake air temperature.
The lower the intake air temperature, the greater the thermistor
resistance value, and the higher the intake air temperature, the
lower the thermistor resistance value (See Fig. 1).
The intake air temperature sensor is connected to the ECM.
The 5 V power source voltage in the ECM is applied to the in-
take air temperature sensor from the terminal THA via a resistor
R.
That is , the resistor R and the intake air temperature sensor are
connected in series. When the resistance value of the intake air
temperature sensor changes in accordance with changes in the
intake air temperature, the potential at terminal THA also
changes. Based on this signal, the ECM increases the fuel in-
jection volume to improve driveability during cold engine opera-
tion.
If the ECM detects the DTC ºP0110º, it operates the fail safe
function in which the intake air temperature is assumed to be
20°C (68°F).

Intake Air Temp. °C (°F)Resistance (kW)Voltage (V)
-20 (-4)16.24.3
0 (32)5.93.4
20 (68)2.52.4
40 (104)1.11.4
60 (140)0.60.9
80 (176)0.30.5
100 (212)0.10.2
DTC No.DTC Detecting ConditionTrouble Area
P0110Open or short in intake air temp. sensor circuit

Open or short in intake air temp. sensor circuit

Intake air temp. sensor

ECM
HINT:
After confirming DTC P0110 use the OBD II scan tool or TOYOTA hand-held tester to confirm the intake
air temperature from ºCURRENT DATAº.
Temperature DisplayedMalfunction
- 40°C (- 40°F)Open circuit
140°C (284°F) or moreShort circuit
DI4SO-01

FI6480
Throttle Position
SensorECM
VCC
VTA1
IDL1
E25V
B+ DI-184
- DIAGNOSTICSENGINE (2JZ-GTE)
412 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0120 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Malfunction
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle body and
detects the throttle valve opening angle. When the throttle valve
is fully closed, the IDL1 contacts in the throttle position sensor
are on, so the voltage at the terminal IDL1 of the ECM becomes
0 V. At this time, a voltage of approximately 0.7 V is applied to
terminal VTA1 of the ECM. When the throttle valve is opened,
the IDL1 contacts go off and thus the power source voltage of
approximately 12 V in the ECM is applied to the terminal IDL1
of the ECM. The voltage applied to the terminal VTA1 of the
ECM increases in proportion to the opening angle of the throttle
valve and becomes approximately 3.2 - 4.9 V when the throttle
valve is fully opened. The ECM judges the vehicle driving condi-
tions from these signals input from terminals VTA1 and IDL1,
and uses them as one of the conditions for deciding the air-fuel
ratio correction, power increases correction and fuel-cut con-
trol etc.
DTC No.DTC Detecting ConditionTrouble Area
P0120
Condition (a) or (b) conditions:
(a) VTA < 0.25 V, and closed throttle position switch is OFF
(b) VTA > 4.9 V
Open or short in throttle position sensor circuit

Throttle position sensor

ECM
HINT:

If there is open circuit in IDL line, DTC P0120 does not indicate.

After confirming DTC P0120 use the OBD II scan tool or TOYOTA hand-held tester to confirm the
throttle valve opening percentage and closed throttle position switch condition.
Throttle valve opening position expressed as percentageTblAThrottle valve fully closedThrottle valve fully openTrouble Area
0 %0 %VC line open
VTA1 line open or short
Approx. 100 %Approx. 100 %E2 line open
DI4SR-01

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

FI7130
Vehicle speed
50 - 65 km/h
(31 - 40 mph)
Idling
IG SW OFF(5) (3)
(1) (2)
1 - 3 min.1 min.
Time
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-193
421 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0130 Heated Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0130
Voltage output of heated oxygen sensor remains at 0.4 V or
more, or 0.55 V or less, during idling after the engine is
warmed up (2trip detection logic)
Heated oxygen sensor

Fuel trim malfunction
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 1 refers to the sensor closer to the engine body.
The heated oxygen sensor output voltage and the short-term fuel trim value can be read using the OBD II
scan tool or TOYOTA hand-held tester.
WIRING DIAGRAM
Refer to page DI-190 for the WIRING DIAGRAM.
CONFIRMATION DRIVING PATTEN
(1) Connect the TOYOTA hand-held tester to the DLC3.
(2) Switch the TOYOTA hand-held tester from normal mode to check mode (See page DI-147).
(3) Start the engine and warm it up with all accessory switches OFF.
(4) Drive the vehicle at 50 - 65 km/h (31 - 40 mph) for 1 - 3 min. to warm up the heated oxygen sensor.
(5) Let the engine idle for 1 min.
HINT:
If a malfunction exists, the MIL will light up during step (5).
NOTICE:
If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.
If you do not have a TOYOTA hand-held tester, turn the ignition switch OFF after performing steps
(3) to (5), then perform steps (3) to (5) again.
DI4SU-01

DI-194
- DIAGNOSTICSENGINE (2JZ-GTE)
422 Author
: Date
:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check for open and short in harness and connector between ECM and heated
oxygen sensor (See page IN-28).
NG Repair or replace harness or connector.
OK
2 Check for heated oxygen sensor data.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC 3.
(b) Warm up engine to normal operating temperature.
CHECK:
Read the heated oxygen sensor output voltage and short-term fuel trim.
RESULT:
PatternHeated oxygen sensor output voltageShort-term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about +20 %
2Rich condition (Changes at 0.4 V or more)Changes at about -20 %
3Except 1 and 2
1, 2 Check fuel trim system (See page DI-201).
3

DI-196
- DIAGNOSTICSENGINE (2JZ-GTE)
424 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0133 Heated Oxygen Sensor Circuit Slow
Response (Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0133
Response time for the heated oxygen sensor voltage output to
change from rich to lean, or from lean to rich, is 1 sec. or more
during idling after the engine is warmed up
(2trip detection logic)

Heated oxygen sensor
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 1 refers to the sensor closer to the engine body.
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0133) being output?
YES Go to relevant DTC chart.
NO
Replace heated oxygen sensor.
DI4SV-01

BE6653S02437A03033
ON
Check Harness A
B72, 71
HT1(+) HTS(+)
ECM
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-197
425 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0135 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 1)
DTC P0141 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0135
When the heater operates, heater current exceeds 2 A
(2 trip detection logic)
Open or short in heater circuit of heated oxygen sensor
Htd htP0135
P0141Heater current of 0.25 A or less when the heater operates
(2 trip detection logic)
Heated oxygen sensor heater

ECM
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 1 refers to the sensor closer to the engine body.

Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to page DI-190 for the WIRING DIAGRAM.
INSPECTION PROCEDURE
1 Check voltage between terminals HT1, HTS of ECM connector and body ground.
PREPARATION:
(a) Connect Check Harness A (See page DI-164).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals HT1, HTS of ECM connec-
tor and body ground.
HINT:

Connect terminal HT1 to bank 1 sensor 1.

Connect terminal HTS to bank 1 sensor 2.
OK:
Voltage: 9 - 14 V
OK Check and replace ECM (See page IN-28).
NG
DI4SW-01

- DIAGNOSTICSENGINE (2JZ-GTE)
DI-199
427 Author
: Date
:
1997 SUPRA (RM502U)
DTC P0136 Heated Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to ºInsufficient Coolant Temp. for Closed Loop Fuel Controlº on page DI-190.
DTC No.DTC Detecting ConditionTrouble Area
P0136
Voltage output of the heated oxygen sensor (bank 1 sensor 2)
remains at 0.4 V or more or 0.5 V or less when the vehicle is
driven at 40 km/h (25 mph) or more after the engine is warmed
up
(2 trip detection logic)

Heated oxygen sensor
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to page DI-190 for the WIRING DIAGRAM.
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0136) being output?
YES Go to relevant DTC chart.
NO
2 Check for open and short in harness and connector between ECM and heated
oxygen sensor (See page IN-28).
NG Repair or replace harness or connector.
OK
DI4SX-01