Diagnosis Procedure (4WAS Main Control Unit)

POWER SUPPLY AND GROUND CIRCUIT


Diagnosis Procedure (4WAS Main Control Unit)

1.CHECK 4WAS MAIN CONTROL UNIT POWER SUPPLY
1. Turn the ignition switch OFF.
2. Disconnect 4WAS main control unit harness connector.
3. Check the voltage between 4WAS main control unit harness connectors and the ground.





4. Turn the ignition switch ON.

CAUTION:
Never start the engine.
5. Check the voltage between 4WAS main control unit harness connectors and the ground.





Is the inspection result normal?
YES - GO TO 2.
NO - Check the following items. Repair or replace the malfunctioning parts.
- 10A fuse (#45) open
- Short among 10A fuse (#45) connector, 4WAS main control unit harness connector No. 27 terminal and the ground
- Open between the ignition switch and 4WAS main control unit harness connector No. 27 terminal
- Ignition switch
2.CHECK 4WAS REAR MOTOR POWER SUPPLY CIRCUIT (1)
1. Turn the ignition switch OFF.
2. Remove 4WAS rear motor relay.
3. Check the continuity between 4WAS rear motor relay harness connector and the ground.





Is the inspection result normal?
YES - GO TO 3.
NO - Repair or replace the harnesses and connectors.
3.CHECK 4WAS REAR MOTOR POWER SUPPLY CIRCUIT (2)
Check the voltage between 4WAS rear motor relay harness connector and the ground.





Is the inspection result normal?
YES - GO TO 4.
NO - Check the following items. Repair or replace the malfunctioning parts.
- 20A fuse (#37) open
- Short among 20A fuse (#37) connector, 4WAS rear motor relay harness connector No. 3 terminal and the ground
- Open between the battery and 4WAS rear motor relay harness connector No. 3 terminal
4.CHECK 4WAS REAR MOTOR POWER SUPPLY CIRCUIT (3)
1. Remove the noise suppressor.
2. Check continuity between the noise suppressor harness connector and the ground.





Is the inspection result normal?
YES - GO TO 5.
NO - Repair or replace the harnesses and connectors.
5.CHECK 4WAS REAR MOTOR POWER SUPPLY CIRCUIT (4)
1. Connect 4WAS main control unit harness connector.
2. Turn the ignition switch ON.

CAUTION:
Never start the engine.
3. Check the voltage between 4WAS main control unit harness connectors.





4. Turn the ignition switch OFF.
Is the inspection result normal?
YES - GO TO 6.
NO - Replace 4WAS main control unit. Refer to Exploded View.
6.CHECK 4WAS REAR MOTOR RELAY
1. Apply 12 V to 4WAS rear motor relay connector No. 1 terminal and No. 2 terminal.

CAUTION:
- Never make the terminals short.
- Connect the fuse between the terminals when applying the voltage.
2. Check the continuity between 4WAS rear motor relay connector terminals.





3. Check the resistance between 4WAS rear motor relay connector terminals.





Is the inspection result normal?
YES - GO TO 7.
NO - Replace 4WAS rear motor relay.
7.CHECK NOISE SUPPRESSOR
Check continuity between the noise suppressor connector terminals.





Is the inspection result normal?
YES - GO TO 8.
NO - Replace the noise suppressor.
8.CHECK 4WAS REAR MOTOR POWER SUPPLY
1. Connect 4WAS main control unit harness connector.
2. Install 4WAS rear motor relay.
3. Install the noise suppressor.
4. Turn the ignition switch ON.

CAUTION:
Never start the engine.
5. Check the voltage between 4WAS main control unit harness connectors and the ground.





Is the inspection result normal?
YES - INSPECTION END.
NO - Replace 4WAS main control unit. Refer to Exploded View.