Inspection Procedure 1: The M.U.T.-III cannot Communicate with the Immobilizer-ECU.


caution Whenever the ECU is replaced, ensure that the communication circuit is normal.

COMMENT ON TROUBLE SYMPTOM


The immobilizer-ECU communicates with the M.U.T.-III via CAN communication. Therefore, communication error of the immobilizer-ECU is suspected.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


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


Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 2.

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

STEP 2. Check the immoblizer-ECU power supply circuit and earth circuit (Refer to Inspection Procedure 4 "Check the immoblizer ECU power supply circuit and earth circuit" .)


Q. Is the check result normal?

Go to Step 3.

Repair the power supply and earth circuit to the immobilizer-ECU.

STEP 3. Retest the system.


Check that immobilizer-ECU communicates with the M.U.T.-III.

Q. Is the check result normal?

Intermittent Malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .)

Replace the immobilizer-ECU and register the ID codes.(Refer to .)