C1684
C1684, C1685 4WAS MAIN CONTROL UNIT COMMUNICATIONDescription
^ 4WAS front control unit and 4WAS main control unit transmit/receive information to/from each other for optimum control of the 4WAS system with the specified 4WAS system line (4WAS communication line) between 4WAS front control unit and 4WAS main control unit.
^ Be careful to repair wirings because 4WAS system specified line adopts twisted-pair wires. Refer to STC-176, "Precautions for Harness Repair". With 4WAS
DTC Logic
C1684-C1685:
DTC CONFIRMATION PROCEDURE
1.RECHECK DTC
With CONSULT-III
1. Turn the ignition switch from OFF to ON.
2. Perform 4WAS front control unit self-diagnosis.
Is DTC "C1684" or "C1685" detected?
YES >> Proceed to diagnosis procedure. Refer to "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis Procedure
1.CHECK COMMUNICATION LINE (1)
1. Turn the ignition switch OFF.
2. Disconnect ABS actuator and electric unit (control unit) harness connector.
3. Disconnect yaw rate/side G sensor harness connector.
4. Disconnect 4WAS front control unit harness connector.
5. Disconnect 4WAS main control unit harness connector.
6. Check the continuity between ABS actuator and electric unit (control unit) harness connector and yaw rate/side G sensor harness connector.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace the harnesses and connectors. Refer to STC-176, "Precautions for Harness Repair". With 4WAS
2.CHECK COMMUNICATION LINE (2)
Check the continuity between ABS actuator and electric unit (control unit) harness connector and the ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace the harnesses and connectors. Refer to STC-176, "Precautions for Harness Repair". With 4WAS
3.CHECK COMMUNICATION LINE (3)
Check the continuity between ABS actuator and electric unit (control unit) harness connector.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair or replace the harnesses and connectors. Refer to STC-176, "Precautions for Harness Repair". With 4WAS
4.CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Check the continuity between ABS actuator and electric unit (control unit) connector. Refer to STC-84, "Component Inspection [ABS Actuator and Electric Unit (Control Unit)]". U1000
Is the inspection result normal?
YES >> GO TO 5.
NO >> Replace ABS actuator and electric unit (control unit).
5.CHECK YAW RATE/SIDE G SENSOR
Check the continuity between yaw rate/side G sensor connector. Refer to BRC-62, "Component Inspection".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Replace yaw rate/side G sensor.
6.CHECK CAN DIAGNOSIS SUPPORT MONITOR (4WAS FRONT CONTROL UNIT)
With CONSULT-III
1. Connect ABS actuator and electric unit (control unit) harness connector.
2. Connect yaw rate/side G sensor harness connector.
3. Connect 4WAS front control unit harness connector.
4. Connect 4WAS main control unit harness connector.
5. Start the engine.
CAUTION:
Stop the vehicle.
6. Perform CAN diagnosis support monitor of 4WAS front control unit.
7. Replace 4WAS main control unit error history. Refer to STC-39, "CONSULT-III Function [4WAS(FRONT)]". Consult-III Function [4WAS(Front)]
What is the indicated item?
All items are "OK" >> GO TO 7,
"TRANSMIT DIAG" is other than "OK" >> GO TO 7,
"4WAS(MAIN)" is other than "OK" >> GO TO 8.
7.CHECK 4WAS FRONT CONTROL UNIT CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect 4WAS front control unit harness connector.
3. Disconnect ABS actuator and electric unit (control unit) harness connector.
4. Check the continuity between 4WAS front control unit harness connector and ABS actuator and electric unit (control unit) harness connector.
5. Check that 4WAS front control unit connector No. 14 terminal and No. 25 are connected properly and not deformed.
Is the inspection result normal?
YES >> Replace 4WAS front control unit.
NO >> Repair or replace the harnesses and connectors. Refer to STC-176, "Precautions for Harness Repair". With 4WAS
8.CHECK 4WAS MAIN CONTROL UNIT CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect 4WAS main control unit harness connector.
3. Disconnect ABS actuator and electric unit (control unit) harness connector.
4. Check the continuity between 4WAS main control unit harness connector and ABS actuator and electric unit (control unit) harness connector.
5. Check that 4WAS main control unit connector No. 31 terminal and No. 32 are connected properly and not deformed.
Is the inspection result normal?
YES >> Replace 4WAS main control unit.
NO >> Repair or replace the harnesses and connectors. Refer to STC-176, "Precautions for Harness Repair". With 4WAS
Component Inspection [ABS Actuator and Electric Unit (Control Unit)]
1.CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
1. Turn the ignition switch OFF.
2. Remove ABS actuator and electric unit (control unit).
3. Check the resistance between ABS actuator and electric unit (control unit) connector terminals.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace ABS actuator and electric unit (control unit).
Component Inspection (Yaw Rate/Side G Sensor)
1.CHECK YAW RATE/SIDE G SENSOR
1. Turn the ignition switch OFF.
2. Remove yaw rate/side G sensor.
3. Check the resistance between yaw rate/side G sensor connector terminals.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace yaw rate/side G sensor.
Special Repair Requirement
BEFORE REPLACING 4WAS FRONT CONTROL UNIT
^ Record the self-diagnosis results (history).
CAUTION:
^ Never erase the memory (history) of self-diagnosis results when replacing 4WAS front control unit after diagnosis.
^ Erase the memory of the self-diagnosis results (record) after printing out or recording all the values of "DATA MONITOR".
BEFORE REPLACING 4WAS MAIN ACTUATOR
^ Record the self-diagnosis results (history).
CAUTION:
^ Never erase the memory (history) of self-diagnosis results when replacing 4WAS main control unit after diagnosis.
^ Erase the memory of the self-diagnosis results (record) after printing out or recording all the values of "DATA MONITOR".
AFTER REPLACING 4WAS FRONT CONTROL UNIT
^ Perform 4WAS front actuator adjustment after replacing 4WAS front control unit. Refer to STC-28, "4WAS FRONT ACTUATOR NEUTRAL POSITION ADJUSTMENT: Special Repair Requirement (Pattern 3)". 4WAS Front Actuator Neutral Position Adjustment