Inspection Procedure 1: The M.U.T.-III cannot communicate with the immobilizer-ECU. <Diesel powered vehicle>


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 54D - Troubleshooting ).

STEP 2. Check the immobilizer-ECU power supply circuit and earth circuit.


Refer to Inspection Procedure 4 "Check the immobilizer ECU power supply circuit and earth circuit" <Diesel powered vehicle>.

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 ).