INSPECTION PROCEDURE 1: Communication Between M.U.T.-III and Transfer-ECU Cannot Be Established

caution

If there is any problem in the CAN bus lines, an incorrect trouble symptom may occur. Prior to this diagnosis, always diagnose the CAN bus lines.
Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

SYMPTOMS

CAN bus line, transfer-ECU power supply circuit, or transfer-ECU may have a problem.

PROBABLE CAUSES

Wrong M.U.T.-III wiring harness
The CAN bus line is defective.
Transfer-ECU power supply circuit malfunction
Malfunction of transfer-ECU
ECU malfunction of other system

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.

Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?

	Check/repair the transfer-ECU power supply circuit. (Refer to .)

	Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting ).