4WAS Communication Circuit

U1000, U1002 4WAS COMMUNICATION CIRCUIT





Description
- 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. Precaution For Harness Repair With 4WAS.




DTC Logic

DTC DETECTION LOGIC





*: Communication line between 4WAS front control unit and 4WAS main control unit

DTC CONFIRMATION PROCEDURE
1.RECHECK DTC
With CONSULT-III
1. Turn the ignition switch from OFF to ON.
2. Perform self-diagnosis for "4WAS(FRONT)".
Is DTC "U1000" or "U1002" detected?
YES - Proceed to diagnosis procedure. SEE 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/decel 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. Precaution For Removal And Installation Of 4WAS Components Precaution For Harness Repair With 4WAS, "Precautions for Harness
Repair".
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. Precaution For Removal And Installation Of 4WAS Components Precaution For Harness Repair With 4WAS, "Precautions for Harness
Repair".
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. Precaution For Removal And Installation Of 4WAS Components Precaution For Harness Repair With 4WAS, "Precautions for Harness
Repair".
4. CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Check the ABS actuator and electric unit (control unit) connector. SEE Component Inspection [ABS Actuator and Electric Unit (Control Unit)], "Component Inspection
[ABS Actuator and Electric Unit (Control Unit)]".
Is the inspection result normal?
YES - GO TO 5.
NO - Replace ABS actuator and electric unit (control unit). Exploded View Removal And Installation, "Removal and Installa-
tion".
5.CHECK YAW RATE/SIDE/DECEL G SENSOR
Check the between yaw rate/side/decel G sensor connector. SEE Component Inspection (Yaw Rate/Side/Decel G Sensor) SEE Special Repair Requirement, "Component Inspection (Yaw
Rate/Side/Decel G Sensor)".
Is the inspection result normal?
YES - GO TO 6.
NO - Replace yaw rate/side G sensor. Removal And Installation.
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/decel 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:
Never drive the vehicle.
6. Perform CAN diagnosis support monitor for "4WAS(FRONT)".
7. Check error history between 4WAS front control unit and 4WAS main control unit. 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 except "OK"-GO TO 7.
"4WAS(MAIN)" is except "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. 4WAS Front Control Unit.
- Before replacing 4WAS front control unit, record the self-diagnosis results (history). SEE Special Repair Requirement.
NO - Repair or replace the harnesses and connectors. Precaution 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. 4WAS Main Control Unit.
- Before replacing 4WAS main control unit, record the self-diagnosis results(history). SEE Special Repair Requirement.
NO - Repair or replace the harnesses and connectors. Precaution 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). Removal And Installation.
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). Removal And Installation.




Component Inspection (Yaw Rate/Side/Decel G Sensor)
1.CHECK YAW RATE/SIDE/DECEL G SENSOR
1. Turn the ignition switch OFF.
2. Remove yaw rate/side/decel G sensor. Removal And Installation.
3. Check the resistance between yaw rate/side/decel G sensor connector terminals.





Is the inspection result normal?
YES - INSPECTION END
NO - Replace yaw rate/side/decel G sensor. Removal And Installation.




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".