Page 601 of 1807

FI7052
A00694
ON
1(+)
DI-186
- DIAGNOSTICSENGINE (2JZ-GTE)
414 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
HINT:
If DTC P0110, P0115 and P0120 are output simultaneously, E2 (sensor ground) may be open.
1 Connect the OBD II scan tool or TOYOTA hand-held tester and read the throttle
valve opening percentage.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC 3.
(b) Turn ignition switch ON and push the OBD II scan tool or TOYOTA hand-held tester main switch ON.
CHECK:
Read the throttle valve opening percentage.
OK:
Throttle valveThrottle valve opening position ex-
pressed as percentage
Fully openApprox. 70 %
Fully closedApprox. 10 %
OK Check for intermittent problems
(See page DI-147).
NG
2 Check voltage between terminal 1 of wire harness side connector and body
ground.
PREPARATION:
(a) Disconnect the throttle position sensor connector.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal 1 of wire harness side con-
nector and body ground.
OK:
Voltage: 4.5 - 5.5 V
NG Go to step 5.
OK
Page 602 of 1807
P24693
4
2
1
A00695
ONCheck Harness A
ECM
B65, 43
VTA1 (+)
E2 (-)
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-187
415 Author: Date:
1997 SUPRA (RM502U)
3 Check throttle position sensor.
PREPARATION:
Disconnect the throttle position sensor connector.
CHECK:
Measure resistance between terminals 1, 2 and 4 of throttle
position sensor.
OK:
TerminalsThrottle valveResistance
1 - 4-3.1 - 7.2 kW
24Fully closed0.34 - 6.3 kW2 - 4Fully open2.4 - 11.2 kW
NG Replace throttle position sensor
(See page SF-44).
OK
4 Check voltage between terminals VTA1 and E2 of ECM.
PREPARATION:
(a) Connect Check Harness A (See page DI-164).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals VTA1 and E2 of ECM.
OK:
Throttle ValveVoltage
Fully closed0.3 - 0.8 V
Fully open3.2 - 4.9 V
NG Check for open and short in harness and con-
nector between ECM and throttle position sen-
sor (VTA line) (See page IN-28).
OK
Check and replace ECM (See page IN-28).
Page 603 of 1807
A00696
ONCheck Harness A
ECM
B65, 41
VCC (+)
E2 (-)
DI-188
- DIAGNOSTICSENGINE (2JZ-GTE)
416 Author: Date:
1997 SUPRA (RM502U)
5 Check voltage between terminals VCC and E2 of ECM.
PREPARATION:
(a) Connect Check Harness A (See page DI-164).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals VCC and E2 of ECM con-
nector.
OK:
Voltage 4.5 - 5.5 V
NG Check and replace ECM (See page IN-28).
OK
Check for open in harness and connector be-
tween ECM and sensor (VC line)
(See page IN-28).
Page 604 of 1807
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-189
417 Author: Date:
1997 SUPRA (RM502U)
DTC P0121 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Range/Performance Problem
CIRCUIT DESCRIPTION
Refer to ºThrottle/Pedal Position Sensor/Switch ºAº circuit malfunctionº on page DI-184.
DTC No.DTC Detecting ConditionTrouble Area
P0121
After the vehicle speed has been exceeded 30 km/h (19 mph)
even once, the output value of the throttle position sensor is
out of the applicable range while the vehicle speed between 30
km/h (19 mph) and 0 km/h (0 mph)
(2 trip detection logic)
Throttle position sensor
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0121) being output?
YES Go to relevant DTC chart.
NO
Replace throttle position sensor.
DI4SS-01
Page 605 of 1807

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
Page 606 of 1807

S02435
Battery
B
W-BEFI No.1
R/B No.2R/B No.2
EFI Main Relay
2
2A 1
B-W
2 22
2
1
2 3 5B-YB-R
8
EA1
B-REA25
B-RGR
W24
48A
BM-REL
OX1
23
1 4
B-L Heated Oxygen
Sensor
(Bank 1 Sensor 1)
B
B
B
EA2
B-R B-R
B-R B-R
R-L
IJ1
IC1
2
4 20
23
1 4 Heated
Oxygen
Sensor
(Bank 1
Sensor 2)
IC1
20
IC1
IJ2
IC1
IJ1
BRBR
BR
BR-WBR-W
8
18 12R-L 9
IJ2
BR
BR-W5 R-L1471
41
72ECM
B+
E1
HT1
E01
OXS
E1
HTS
E01
EDEBBR
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-191
419 Author: Date:
1997 SUPRA (RM502U)
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Connect the OBD II scan tool or TOYOTA hand-held tester and read value for
voltage output of heated oxygen sensor.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC 3.
(b) Warm up engine to normal operation temperature.
CHECK:
Read voltage output of heated oxygen sensor (bank 1 sensor 1) when engine is suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 times using accelerator pedal.
OK:
Both heated oxygen sensors (bank 1 sensor 1) output a RICH signal (0.45 V or more) at least
once.
OK Check and replace ECM (See page IN-28).
NG
Page 607 of 1807
DI-192
- DIAGNOSTICSENGINE (2JZ-GTE)
420 Author: Date:
1997 SUPRA (RM502U)
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
Replace heated oxygen sensor.
Page 608 of 1807

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