Inspection Procedure 10: The auto lamp function does not work normally.


caution Whenever the ECU is replaced, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

OPERATION


The ETACS-ECU operates this function in accordance with the input signals from lighting control sensor and column switch (auto lamp switch).

COMMENTS ON TROUBLE SYMPTOM


If the auto lamp function does not work normally, the above input signal circuit(s) or the ETACS-ECU may have a problem.

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. M.U.T.-III diagnosis code


Check if diagnosis code is set to the LIN.

Q. Is the diagnosis code set?

Refer to diagnosis code chart .

Go to Step 3.

STEP 3. M.U.T.-III other system 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 4.

STEP 4. Check that the headlamps operate.


Check that the headlamps (low-beam) illuminate normally.

Q. Is the check result normal?

Go to Step 5.

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

STEP 5. Lighting control sensor check


Check the lighting control sensor. Refer to .

Q. Is the check result normal?

Go to Step 6.

Replace the lighting control sensor.

STEP 6. Retest the system


Check that the auto lamp function works normally.

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 and register the ID codes (Refer to ).