Inspection Procedure 1: A/T-ECU cannot communicate with M.U.T.-III.




SYMPTOMS




PROBABLE CAUSES



  • Damaged wiring harness and connectors
  • Malfunction of A/T-ECU

DIAGNOSTIC PROCEDURE


STEP 1. Check for short circuit in power supply line between the fusible link and the A/T control relay connector.


Q. Is the check result normal?

Go to Step 2.
Repair the connector(s) or wiring harness.

STEP 2. Check for short circuit in VIG1, VIG2 line between the A/T control relay connector and the A/T-ECU connector.


Q. Is the check result normal?

Go to Step 3.
Repair the connector(s) or wiring harness.

STEP 3. Check for open circuit in GND1, GND2 line between the A/T-ECU connector and earth.


Q. Is the check result normal?

Go to Step 4.
Repair the connector(s) or wiring harness.

STEP 4. Retest the system.


Recheck the trouble symptom.

Q. Does the malfunction take place again?

Replace A/T-ECU.
Intermittent malfunction.