Page 961 of 1807
DI-670
- DIAGNOSTICSCRUISE CONTROL SYSTEM
898 Author: Date:
1997 SUPRA (RM502U)
Ignition switch ON10 - 16 V
CCSGND
Ignition switch ON
CANCEL switch hold ON4.2 - 8.7 V
CCS e GND
(C16-18 eC16-13)L e W-BIgnition switch ON
SET/COAST switch hold ON2.5 - 6.2 V
Ignition switch ON
RES/ACC switch hold ON0.8 - 3.6 V
CMS e GNDRYWB
Ignition switch ON
Main switch ONBelow 1 VCMS e GND
(C16-19 eC16-13)R-Y e W-BIgnition switch ON
Main switch OFF10 - 16 V
Ignition switch ON10 - 16 V
SPD e GND
(C16-20 eC16-13)P e W-BDuring driving
Repeatedly change
from below 1 V to
10 - 16 V
IDL e GNDRBWB
Ignition switch ON
Throttle valve fully closedBelow 1 VIDL e GND
(C16-21 eC16-13)R-B e W-BIgnition switch ON
Throttle valve fully opened10 - 16 V
ECT e GNDRLWB
During driving
Gear position O/DBelow 1 VECT e GND
(C16-22 eC16-13)R-L e W-BDuring driving
Gear position 3rd10 - 16 V
Page 962 of 1807

DI4XP-01
- DIAGNOSTICSCRUISE CONTROL SYSTEM
DI-671
899 Author: Date:
1997 SUPRA (RM502U)
PROBLEM SYMPTOMS TABLE
SymptomSuspect AreaSee page
Cruise control system does not set.
Cruise control system does not operate.
Input signal check No.4: OK
1. ECU Power Source Circuit
2. Wire Harness
3. Main Switch Circuit
4. Control Switch Circuit
5. Stop Light Switch Circuit
6. PNP Switch or Clutch Switch Circuit
7. Actuator Control Cable
8. Actuator Motor Circuit
9. Cruise Control ECU
Input signal check No.4: NG
1. Vehicle Speed Sensor Circuit
2. Cruise Control ECU
DI-699
DI-704
DI-682
DI-687
DI-694,
DI-697
DI-710
DI-673
IN-28
DI-679
IIN-28
Indicator light does not light up.
1. Wire Harness
2. CRUISE MAIN Indicator Light Circuit
3. Cruise Control ECU
DI-706
IIN-28
Vehicle speed drop when the cruise control switch turned to SET.
1. Actuator Control Cable
2. ECU Power Source Circuit
3. Idle Signal Circuit
4. Actuator Motor Circuit
5. Cruise Control ECUDI-710
DI-699
DI-685
DI-673
IN-28
Set speed deviates on high or low side.
Input signal check No.4: OK
1. Vehicle Speed Sensor Circuit
2. Actuator Control Cable
3. ECU Power Source Circuit
4. Actuator Motor Circuit
5. Cruise Control ECU
Input signal check No.4: NG
1. Cruise Control ECU
DI-679
DI-710
DI-699
DI-673
IN-28
IN-28
Vehicle speed fluctuates when cruise control switch turn to SET.
1. Vehicle Speed Sensor Circuit
2. Actuator Control Cable
3. Idle Signal Circuit
4. ECT Communication Circuit
5. Actuator Motor Circuit
6. Cruise Control ECUDI-679
DI-710
DI-685
DI-690
DI-673
IN-28
Acceleration response is sluggish when cruise control switch turn
to ºACCELº or ºRESUMEº.
Input signal check No.4: OK
1. Actuator Control Cable
2. Vehicle Speed Sensor Circuit
3. Actuator Motor Circuit
4. Cruise Control ECU
Input signal check No.4: NG
1. Control Switch Circuit
2. Cruise Control ECU
DI-673
DI-679
DI-710
IN-28
DI-682
IN-28
Set speed does not cancel when brake pedal depressed.
Input signal check No.3: OK
1. Cruise Control ECU
Input signal check No.3: NG
1. Stop Light Switch Circuit
2. Cruise Control ECU
IN-28
DI-687
IIN-28
Cruise control does not cancel when transmission is shifted to
except D position. (A/T)
Input signal check No.3: OK
1. Cruise Control ECU
Input signal check No.3: NG
1. PNP Switch Circuit
2. Cruise Control ECU
IIN-28
DI-694
IN-28
Page 963 of 1807

DI-672
- DIAGNOSTICSCRUISE CONTROL SYSTEM
900 Author: Date:
1997 SUPRA (RM502U) Cruise control does not cancel when clutch pedal depressed.
Input signal check No.3: OK
1. Cruise Control ECU
Input signal check No.3: NG
1. Clutch Switch Circuit
2. Cruise Control ECU
IN-28
DI-697
IN-28
Cruise control does not cancel when cruise control switch turned
to CANCEL.
Input signal check No.3: OK
1. Cruise Control ECU
Input signal check No.3: NG
1. Control Switch Circuit
2. Cruise Control ECU
IN-28
DI-682
IN-28
Vehicle speed does not decrease when cruise control switch
turned to COAST.
Input signal check No.1: OK
1. Actuator Motor Circuit
2. Actuator Control Cable
3. Vehicle Speed Sensor Circuit
4. Cruise Control ECU
Input signal check No.1: NG
1. Control Switch Circuit
2. Cruise Control ECU
DI-673
DI-710
DI-679
IIN-28
DI-682
IN-28
Vehicle speed does not accelerate when cruise control switch
turned to ACCEL.
Input signal check No.2: OK
1. Actuator Motor Circuit
2. Actuator Control Cable
3. Vehicle Speed Sensor Circuit
4. Cruise Control ECU
Input signal check No.2: NG
1. Control Switch Circuit
2. Cruise Control ECU
DI-673
DI-710
DI-679
IIN-28
DI-682
IN-28
Vehicle speed does not return to memorized speed when cruise
control switch turned to RESUME.
Input signal check No.2: OK
1. Actuator Motor Circuit
2. Actuator Control Cable
3. Vehicle Speed Sensor Circuit
4. Cruise Control ECU
Input signal check No.2: NG
1. Control Switch Circuit
2. Cruise Control ECU
DI-673
DI-710
DI-679
IN-28
DI-682
IN-28
Speed can be set below about 40 km/h (25 mph).
Input signal check No.4: OK
1. Cruise Control ECU
Input signal check No.4: NG
1. Vehicle Speed Sensor Circuit
2. Cruise Control ECU
IN-28
DI-679
IN-28
Cruise control does not cancel when speed is less than 40 km/h
(25 mph).
Input signal check No.4: OK
1. Actuator Motor Circuit
2. Cruise Control ECU
Input signal check No.4: NG
1. Vehicle Speed Sensor Circuit
2. Cruise Control ECU
DI-673
IIN-28
DI-679
IIN-28
Page 964 of 1807
DI4XQ-01
Duty Ratio =A + BA
x 100 (%)
ON
OFFA
B
1 cycle
I02714
Cruise Control ActuatorCruise Control ECU
MC2
C4
1G-R
C4LG9
IB6
15
IB6G-R
LG11
C16
C1612MC
MO
MO
- DIAGNOSTICSCRUISE CONTROL SYSTEM
DI-673
901 Author: Date:
1997 SUPRA (RM502U)
CIRCUIT INSPECTION
DTC 11, 15 Actuator Motor Circuit
CIRCUIT DESCRIPTION
The actuator motor is operated by signals from the ECU. Acceleration and deceleration signals are trans-
mitted by changes in the Duty Ratio (See note below).Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity
in one cycle, and B is the period of non-continuity, then.
DTC No.Detection ItemTrouble Area
11Short in actuator motor circuit
Cruise control actuator
Harness or connector between actuator and cruise control
ECU
Cruise control ECU
15Open in actuator motor circuitCruise control actuator
WIRING DIAGRAM
Page 965 of 1807
N19821
1 2
DI-674
- DIAGNOSTICSCRUISE CONTROL SYSTEM
902 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check resistance between terminals MO and MC of cruise control actuator.
PREPARATION:
(a) Ignition switch ON.
(b) Disconnect actuator connector.
CHECK:
Measure resistance between terminals 1 and 2.
HINT:
If control plate position is fully opened or fully closed, resistance
can not measure.
OK:
Resistance: more than 4.2 W
NG Replace cruise control actuator.
OK
2 Check wire harness and connector between terminals MO of cruise control ECU
and MO of cruise control actuator (See page IN-28).
NG Repair or replace harness or connector.
OK
Replace cruise control ECU
(See page IN-28).
Page 966 of 1807

I02715
Cruise Control Actuator
Magnetic ClutchGND4
C4
C43
LBR-Y
R-L17
IB6
8
IB6W-B
R-L
Battery
STOP10
1I
J/B No.1WCruise Control ECU
13
43
21 S11
S11S11
S11
Stop Light SwitchB-W
G-W G-WC16
C16
C1610
16
To Light Failure SensorGND
L
STP-
- DIAGNOSTICSCRUISE CONTROL SYSTEM
DI-675
903 Author: Date:
1997 SUPRA (RM502U)
DTC 12 Magnetic Clutch Circuit
CIRCUIT DESCRIPTION
This circuit turns on the magnetic clutch inside the actuator during cruise control operation according to the
signal from the ECU. If a malfunction occurs in the actuator or speed sensor, etc. during cruise control opera-
tion, the rotor shaft between the motor and control plate is released.
When the brake pedal is depressed, the stoplight switch turns on, supplying electrical power to the stoplight.
Power supply to the magnetic clutch is mechanically cut and the magnetic clutch is turned OFF.
When driving downhill, if the vehicle speed exceeds the set speed by 15 km/h (6 mph) above the set speed,
then cruise control at the set speed is resumed.
DTC No.Detection ItemTrouble Area
12Short in magnetic clutch circuit
Open (0.8 sec.) in magnetic clutch circuit
Cruise contorl actuator magnetic clutch
Harness or connector between ECU and magnetic clutch,
magnetic clutch and body ground
Cruise control ECU
WIRING DIAGRAM
DI4XR-01
Page 967 of 1807
N08843
J/B No.1
STOP Fuse
DI-676
- DIAGNOSTICSCRUISE CONTROL SYSTEM
904 Author: Date:
1997 SUPRA (RM502U)
INSPECTION PROCEDURE
1 Check STOP fuse.
PREPARATION:
Remove STOP fuse from J/B No.1.
CHECK:
Check fuse continuity.
OK:
There is continuity.
NG Replace STOP fuse.
OK
2 Check harness and connector between actuator and cruise control actuator (See
page IN-28).
NG Repair or replace harness or connector.
OK
Check and replace cruise control ECU (See
page IN-28).
Page 968 of 1807
N19825
4
3
- DIAGNOSTICSCRUISE CONTROL SYSTEM
DI-677
905 Author: Date:
1997 SUPRA (RM502U)
DTC 14 Actuator Mechanical Malfunction
CIRCUIT DESCRIPTION
See page DI-673.
WIRING DIAGRAM
See page DI-673.
INSPECTION PROCEDURE
1 Check actuator arm locking operation.
PREPARATION:
(a) Ignition switch OFF.
(b) Disconnect actuator connector.
CHECK:
(a) Connect the positive lead from the battery to the termi-
nal 3 of actuator and the negative lead to terminal 4.
NOTICE:
Do not connect the high tension cables to the wrong bat-
tery terminal. You will damage the cruise control actuator.
(b) Move the control plate by hand.
OK:
Control plate does not move.
NG Replace cruise control actuator.
OK
DI4XS-01