Inspection Procedure 4: The headlamps do not illuminate when the passing switch is turned ON.

  • Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
  • When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine cannot be started. Register the encrypted code as described in Immobilizer System - How to Register Key ID .)


If both headlamps (low-beam and high-beam) do not illuminate, the passing switch input circuit or ETACS-ECU may have a problem.



STEP 1. Check the operation of the headlamps.

Check that the low-beam and high-beam headlamps illuminate normally.

Q. Is the check result normal?

Go to Step 2.

Refer to Inspection Procedure 1 "None of the low-beam headlamps illuminate." and Inspection Procedure 2 "None of the high-beam headlamps illuminate." .

STEP 2. M.U.T.-III diagnosis code

Check if diagnosis code is set to the ETACS-ECU.

Q. Is the diagnosis code set?

Troubleshoot the ETACS-ECU. Refer to .

Go to Step 3.

STEP 3. Retest the system

Check that the headlamps (low-beam and high-beam) illuminates normally when turning ON the passing switch.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).

Replace the ETACS-ECU.