Page 689 of 1807

S03236
VSV for Exhaust Gas Control Valve
Actuator (for Exhaust Gas Control Valve)
VSV for Exhaust
Bypass Valve
Actuator
(for Exhaust
Bypass Valve)
VSV for Intake Air Control Valve
Actuator (for Intake Air Control Valve) Exhaust Manifold
Intake Manifold CAC Air Bypass Valve Actuator
(for Waste Gate Valve)Air
Cleaner VSV for Waste
Gate Valve
Waste Gate
Valve
ECM
DI-274
- DIAGNOSTICSENGINE (2JZ-GTE)
502 Author: Date:
1997 SUPRA (RM502U)
DTC P1512 Boost Pressure High Malfunction
CIRCUIT DESCRIPTION
To control maximum turbocharging pressure the turbocharger system includes a waste gate valve or exhaust
bypass valve controlled by an actuator. The actuator is controlled by the manifold pressure which is duty
controlled by the VSV based on signals from the ECM.
If the ECM detects the below diagnosis conditions, it operates the fail safe function in which the ECM stops
fuel injection.
DTC No.DTC Detecting ConditionTrouble Area
P1512
Under the following conditions (a), (b) and (c):
(a) After the engine is warmed up
(b) Engine rotation speed 3,400 rpm or less
(c) Under the condition with +740 mmHg or more of intake pipe
pressure
(2 trip detection logic)
Actuator (for waste gate valve and exhaust bypass valve)
Short in VSV for waste gate valve and exhaust bypass valve
circuit
ECM
DI4TJ-01
Page 690 of 1807
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-275
503 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
TOYOTA hand-held tester
1 Connect the TOYOTA hand-held tester and check operation of VSV for waste
gate valve.
OK Go to step 3.
NG
2 Check VSV for waste gate valve (See page SF-63).
NG Replace VSV for waste gate valve.
OK
3 Connect the TOYOTA hand-held tester and check operation of VSV for exhaust
bypass valve (See page DI-266).
OK Go to step 6.
NG
4 Check VSV for exhaust bypass valve (See page SF-67).
NG Replace VSV for exhaust bypass valve.
OK
Page 691 of 1807
DI-276
- DIAGNOSTICSENGINE (2JZ-GTE)
504 Author: Date:
1997 SUPRA (RM502U)
5 Check for open and short in harness and connector between EFI main relay
(Marking: EFI MAIN) and ECM (See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-28).
6 Check connection of vacuum hose (See page EC-2).
NG Repair or replace.
OK
7 Check operation of waste gate valve (See page TC-18).
NG Replace No.1 turbocharger.
OK
8 Check operation of exhaust bypass valve (See page TC-18).
NG Replace No.2 turbocharger.
OK
Check and replace ECM (See page IN-28).
Page 692 of 1807
BE6653S05421
A03144
ON
Check Harness A
VSV3 (+)
VSV4 (+)
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-277
505 Author: Date:
1997 SUPRA (RM502U)
OBDII scan tool (excluding TOYOTA hand-held tester)
1 Check VSV for waste gate valve (See page SF-63).
NG Replace VSV for waste gate valve.
OK
2 Check VSV for exhaust bypass valve (See page SF-67).
NG Replace VSV for exhaust bypass valve.
OK
3 Check voltage between terminal VSV3, VSV4 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 terminal VSV3, VSV4 of ECM con-
nector and body ground.
OK:
Voltage: 9 - 14 V
NG Check and repair harness or connector be-
tween VSV for waste gate valve and ECM
(See page IN-28).
OK
Page 693 of 1807
DI-278
- DIAGNOSTICSENGINE (2JZ-GTE)
506 Author: Date:
1997 SUPRA (RM502U)
4 Check connection of vacuum hose (See page EC-2).
NG Repair or replace.
OK
5 Check operation of waste gate valve (See page TC-18).
NG Replace No.1 turbocharger.
OK
6 Check operation of exhaust bypass valve (See page TC-18).
NG Replace No.2 turbocharger.
OK
Check and replace ECM (See page IN-28).
Page 694 of 1807
S05426
From
BatteryR/B
No.2 2
2A
ALT
R/B
No.2
POWER
22W-L
J/B No.1 210
1B 1ESTOP
WStop Light
Switch
21G-W11
IJ1G-W4
A
STPECM
J/B
No.1 1
101H
1C
Light
Failure
Sensor
To Stop LightG-W
7
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-279
507 Author: Date:
1997 SUPRA (RM502U)
DTC P1520 Stop Light Switch Signal Malfunction
Only for A/T
CIRCUIT DESCRIPTION
This signal is used to detect when the brakes have been applied. The STP signal voltage is the same as
the voltage supplied to the stop lights.
The STP signal is used mainly to control the fuel cut-off engine speed. (The fuel cut-off engine speed is
reduced slightly when the vehicle is braking.)
DTC No.DTC Detecting ConditionTrouble Area
P1520
The stop light switch does not turn off even once the vehicle is
driven.
(2 trip detection logic)Short in stop light switch signal circuit
Stop light switch
ECM
WIRING DIAGRAM
DI4TK-01
Page 695 of 1807

A00726
ON
ONBrake Pedal
DepressedBrake Pedal
Released
Check Harness A
ECM
A4
STP(+)
DI-280
- DIAGNOSTICSENGINE (2JZ-GTE)
508 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check operation of stop light.
PREPARATION:
Check if the stop lights go on and off normally when the brake
pedal is operated and released.
NG Check and repair stop light circuit.
OK
2 Check STP signal.
When using TOYOTA hand-held tester:
PREPARATION:
(a) Connect the TOYOTA hand-held tester to the DLC3.
(b) Turn the ignition switch ON and TOYOTA hand-held tes-
ter main switch ON.
CHECK:
Read the STP signal on the TOYOTA hand-held tester.
OK:
Break pedal is depressed: STP ... ON
Break pedal is released: STP ... OFF
When not using TOYOTA hand-held tester:
PREPARATION:
(a) Connect Check Harness A (See page DI-164).
(b) Turn ignition switch ON.
CHECK:
Check voltage between terminal STP of ECM and body ground.
OK:
Brake pedalVoltage
Depressed7.5 - 14 V
ReleasedBelow 1.5 V
OK Check for intermittent problems
(See page DI-147).
NG
Page 696 of 1807
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-281
509 Author: Date:
1997 SUPRA (RM502U)
3 Check harness and connector between ECM and stop light switch
(See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace ECM.