Page 825 of 1807
F03393
Trottle Conrol ECU
5V
5V EFIF
EFI+
EFI-
GE11 P
B
W
(Shielded) ECM
EFIF
EFI+
EFI-
T15
T1517
7
20
15
T15 67
E9
27
E10
26
E10T15
DI-534
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
762 Author: Date:
1997 SUPRA (RM502U)
DTC 43 ECM Communication Circuit Malfunction
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
43ECM normal communication data is not received for 5 sec. or
more.Wire harness and connector (EFI+ and EFI- circuit)
ECM
Throttle control ECU
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check for open and short in harness and connector between terminals EFI+ and
EFI- of throttle control ECU and ECM (See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace ECM or throttle control
ECU.
DI4W4-01
Page 826 of 1807
F03368
Throttle Control
ECU R/B No.5
Throttle Control Relay
(TRAC Solenoid Relay)
R/B
No.2
Battery+B
RLY-
RLY+
E01 9
12
4
13
BR L-B BR-BL-R 14
11
12
L-B L-Y
TRAC
L-R
BR-B
B
2
12A2
15
4 3
51
65
5
T15
EC IB5 T16T16T16
IB5 IB5
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
DI-535
763 Author: Date:
1997 SUPRA (RM502U)
DTC 51, 52 Power Source Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
51In case power source voltage comes down, sub-throttle valve
angle difference occurs.Wire harness and connector (+B and E01 circuit)
Throttle control ECU
52Engine speed is 500 rpm or more and throttle relay is ON and
ECU terminal +B voltage is less than 8 V for 10 sec. or more.
Battery
IC regulator
Wire harness and connector (+B and E01 circuit)
Throttle control ECU
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check battery positive voltage.
OK:
Voltage: 10 - 14 V
NG Check and repair the charging system.
OK
DI4W5-01
Page 827 of 1807
BE6653F03395F03396
ON
E01
DI-536
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
764 Author: Date:
1997 SUPRA (RM502U)
2 Check for open and short in harness and connector between terminal +B of
throttle control ECU and throttle control relay (See page IN-28).
NG Repair or replace harness or connector.
OK
3 Check voltage between terminals +B and E01 of throttle control ECU connector.
PREPARATION:
(a) Remove throttle control ECU with connectors still con-
nected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals +B and E01 of throttle con-
trol ECU connector.
OK:
Voltage: 9 - 14 V
OK Check and replace throttle control ECU.
NG
Page 828 of 1807
BE6653F03397F03398
LOCK
E01
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
DI-537
765 Author: Date:
1997 SUPRA (RM502U)
4 Check continuity between terminal E01 of throttle control ECU connector and
body ground.
CHECK:
Measure resistance between terminal E01 of throttle control
ECU connector and body ground.
OK:
Resistance: 1 W or less
NG Repair or replace harness or connector.
OK
Check for open in harness and connector between throttle control ECU and battery
(See page IN-28).
Page 829 of 1807

BR3583
BR3582F00010
Speed Sensor
High Speed Rotor
+V
-VLow SpeedTo ECU Magnet
CoilNS
DI-538
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
766 Author: Date:
1997 SUPRA (RM502U)
DTC 61, 62, 63, 64 Speed Sensor Circuit
CIRCUIT DESCRIPTION
The speed sensor detects the wheel speed and sends the ap-
propriate signals to the ECU. These signals are used to control
both the ABS and TRAC control systems. The front and rear ro-
tors each have 48 serrations.
When the rotors rotate, the magnetic field emitted by the perma-
nent magnet in the speed sensor generates an AC voltage.
Since the frequency of this AC voltage changes in direct propor-
tion to the speed of the rotor, the frequency is used by the ECU
to detect the speed of each wheel.
DTC No.DTC Detecting ConditionTrouble Area
61,62,63,64
When the brake switch is OFF, one of the symmetrical wheels'
speed becomes one eight or less of the slowest speed of other
3 wheels continuously for 10 sec. or more.Right front, left front, right rear and left rear speed sensor
Wire harness and connector (FRO, FLO, RRO and RLO
circuit)
Throttle control ECU
HINT:
DTC No.61 is for the right front speed sensor.
DTC No.62 is for the left front speed sensor.
DTC No.63 is for the right rear speed sensor.
DTC No.64 is for the left rear speed sensor.
DI4W6-01
Page 830 of 1807
BR5402
Throttle Control ECU
12V
FRO
FLO
RRO
RLO LG-B
O
Y-B
GR-R
Speed
Sensor FRO
FLO
RRO
RLO ABS ECU
16
T16
8
15
7 7
20
A20
A20
A206
9 A20T16
T16
T16
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
DI-539
767 Author: Date:
1997 SUPRA (RM502U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If the DTC is output from the ABS warning light, troubleshoot the ABS first.
1 Check for open and short in harness and connector between terminals FRO,
FLO, RRO, RLO of ABS ECU and throttle control ECU (See page IN-28).
NG Repair or replace harness or connector.
OK
Page 831 of 1807

R14205
21
R14213
12
DI-540
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
768 Author: Date:
1997 SUPRA (RM502U)
2 Check speed sensor.
Front
PREPARATION:
(a) Remove front fender splash shield.
(b) Disconnect speed sensor connector.
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector.
OK:
Resistance: 0.6 - 2.5 kW
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector and body ground.
OK:
Resistance: 1 MW or higher
Rear
PREPARATION:
(a) Remove rear seat cushion, seat back and quarter trim
panel.
(b) Disconnect speed sensor connector.
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector.
OK:
Resistance: 0.65 - 1.8 kW
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector and body ground.
OK:
Resistance: 1 MW or higher
NG Replace speed sensor.
NOTICE:
Check the speed sensor signal last (See page DI-501).
OK
3 Check for open and short in harness and connector between each speed sensor
and ABS ECU (See page IN-28).
NG Repair or replace harness or connector.
OK
Page 832 of 1807
- DIAGNOSTICSABS & TRACTION CONTROL SYSTEM
DI-541
769 Author: Date:
1997 SUPRA (RM502U)
4 Check for open and short in harness and connector between terminals FRO,
FLO, RRO, RLO of throttle control ECU and ABS ECU (See page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace throttle control ECU.