TOYOTA SUPRA 1997 Service Repair Manual

A00730
ONCheck Harness A
ECM
A1
IGSW(+)
N08417
J/B No.1
IGN Fuse
DI-306
- DIAGNOSTICSENGINE (2JZ-GTE)
534 Author
: Date
:
1997 SUPRA (RM502U)
3 Check voltage between terminal IGSW of ECM connector and body ground.
PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminal IGSW of ECM and body
ground.
OK:
Voltage: 9 - 14 V
OK Go to step 6.
NG
4 Check IGN fuse.
PREPARATION:
Remove IGN fuse from J/B No.1.
CHECK:
Check continuity of IGN fuse.
OK:
Continuity
NG Check for short in all the harness and compo-
nents connected to IGN fuse.
OK

A00731
ONCheck Harness A
ECM
A24 M-REL (+)
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-307
535 Author
: Date
:
1997 SUPRA (RM502U)
5 Check ignition switch (See page BE-13).
NG Replace ignition switch.
OK
Check for open and short in harness and connector between battery and ignition switch, ignition
switch and ECM (See page IN-28).
6 Check voltage between terminal M-REL of ECM connector and body ground.
PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminal M-REL of ECM and body
ground.
OK:
Voltage: 9 - 14 V
NG Check and replace ECM.
OK
7 Check EFI fuse (See page DI-284).
NG Check for short in all the harness and compo-
nents connected to EFI fuse.
OK

DI-308
- DIAGNOSTICSENGINE (2JZ-GTE)
536 Author
: Date
:
1997 SUPRA (RM502U)
8 Check EFI main relay (Marking: EFI MAIN) (See page SF-54).
NG Replace EFI main relay (Marking: EFI MAIN).
OK
9 Check for open and short in harness and connector between terminal M-REL of
ECM connector and body ground (See page IN-28).
NG Repair or replace harness or connector.
OK
Check for open and short in harness and connector between terminal +B of ECM connector and
battery (See page IN-28).

FI6897
Pressure
Regulator
From Fuel Tank To
Fuel
Tank
(Return) Intake
Manifold ECMVSV
S03472
Battery
B
EB
W-BEFI No.1
R/B
No.2
1
2A2
B-W
222
2
EFI Relay
R/B
No.2
21 5
3B-R5
EA2
B-Y
EA18
VSV for Fuel
Pressure Control B-R1
2W-L73
B
GR24
AECM
FPU
E01
B+
M-REL
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-309
537 Author
: Date
:
1997 SUPRA (RM502U)
Fuel Pressure Control Circuit
CIRCUIT DESCRIPTION
The ECM turns on a VSV (Vacuum Switching Valve) to draw the
air into the diaphragm chamber of the pressure regulator if it de-
tects that the temperature of the engine coolant is too high dur-
ing engine staring.
The air drawn into the chamber increases the fuel pressure to
prevent fuel vapor lock at high engine temperature in order to
help the engine start when it is warm.
Fuel pressure control ends approx. 120 sec. after the engine is
started.
WIRING DIAGRAM
DI4TV-01

A00732
ON
E
Air Filter
E
G VSV: ON
VSV: OFF
DI-310
- DIAGNOSTICSENGINE (2JZ-GTE)
538 Author
: Date
:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
TOYOTA hand-held tester
1 Connect the TOYOTA hand-held tester and check operation of VSV for fuel pres-
sure control.
PREPARATION:
(a) Connect the TOYOTA hand-held tester to the DLC3.
(b) Turn ignition switch ON and TOYOTA hand-held tester
main switch ON.
(c) Select the ACTIVE TEST mode on the TOYOTA hand-
held tester.
CHECK:
Check operation of VSV when VSV is operated by the TOYOTA
hand-held tester.
OK:
VSV is ON:
Air from pipe E flows out through the air filter.
VSV is OFF:
Air from pipe E flows out through pipe G.
OK Check and repair fuel pressure regulator
(See page SF-1).
NG
2 Check VSV for fuel pressure control (See page SF-59).
NG Replace VSV for fuel pressure control.
OK

A00733
ON
Check Harness A
B73
FPU(+)
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-31 1
539 Author
: Date
:
1997 SUPRA (RM502U)
3 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).
OBDII scan tool (excluding TOYOTA hand-held tester)
1 Check VSV for fuel pressure control (See page SF-59).
NG Replace VSV for fuel pressure control.
OK
2 Check voltage between terminal FPU 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 FPU of ECM connector and
body ground.
OK:
Voltage: 9 - 14 V
NG Check for open and short in harness and con-
nector between EFI main relay (Marking: EFI
MAIN) and ECM (See page IN-28).
OK

DI-312
- DIAGNOSTICSENGINE (2JZ-GTE)
540 Author
: Date
:
1997 SUPRA (RM502U)
3 Check fuel pressure regulator (See page SF-1).
NG Repair or replace.
OK
Check and replace ECM (See page IN-28).

P19604
A/C Amplifier
5 V
6
A14L-R31
II1L-R34
AAC1ECM
E1
- DIAGNOSTICSENGINE (2JZ-GTE)
DI-313
541 Author
: Date
:
1997 SUPRA (RM502U)
A/C Cut Control Circuit
CIRCUIT DESCRIPTION
This circuit cuts air conditioning operation during vehicle acceleration in order to increase acceleration per-
formance. During acceleration with the vehicle speed at 25 km/h (16 mph) or less, engine speed at 1,200
rpm or less and throttle valve opening angle at 60° or more, the A/C magnet switch is turned OFF for several
seconds.
WIRING DIAGRAM
INSPECTION PROCEDURE
TOYOTA hand-held tester
1 Connect the TOYOTA hand-held tester and check operation of air conditioning
cut control.
PREPARATION:
(a) Connect the TOYOTA hand-held tester to the DLC3.
(b) Turn ignition switch ON and push TOYOTA hand-held tester main switch ON.
(c) Start the engine and air conditioning switch ON.
HINT:
A/C magnetic clutch is turned ON.
(d) Select the ACTIVE TEST mode on the TOYOTA hand-held tester.
CHECK:
Check operation of A/C magnetic clutch cut when air conditioning cut control is operated by the TOYOTA
hand-held tester.
OK:
A/C magnetic clutch is turned OFF.
DI4TW-01

S03240
Check Harness A
AC1 (+)
DI-314
- DIAGNOSTICSENGINE (2JZ-GTE)
542 Author
: Date
:
1997 SUPRA (RM502U)
OK Proceed to next circuit inspection shown on
matrix chart (See page DI-169).
NG
2 Check for open and short in harness and connector between ECM and A/C am-
plifier (See page IN-28).
NG Repair or replace harness or connector.
OK
3 Check voltage between terminal AC1 of ECM connector and body ground.
PREPARATION:
(a) Connect Check Harness A (See page DI-164).
(b) Start the engine.
CHECK:
Measure voltage between terminal AC1 of ECM connector and
body ground when A/C switch is turned to ON and OFF.
OK:
A/C Switch ConditionVoltage
ON0 - 1.5 V
OFF7.5 - 14 V
NG Check and replace A/C amplifier.
OK
Check and replace ECM (See page IN-28).

- DIAGNOSTICSENGINE (2JZ-GTE)
DI-315
543 Author
: Date
:
1997 SUPRA (RM502U)
OBDII scan tool (excluding TOYOTA hand-held tester)
1 Check voltage between terminal AC1 of ECM and body ground (See page
DI-313, step 3).
OK Check and replace ECM (See page IN-28).
NG
2 Check for open and short in harness and connector between ECM and A/C am-
plifier (See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace A/C amplifier.