Inspection Procedure 1: The system is not activated when the automatic high beam switch is operated.

caution

Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM

When the operation indicator lamp in the combination meter does not illuminate, the column switch (automatic high beam switch), the ETACS-ECU or the FCM/LDW/AHB-ECU may be defective.

PROBABLE CAUSES

Malfunction of the column switch
Malfunction of the ETACS-ECU
Defective FCM/LDW/AHB-ECU circuit system

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III other system diagnosis code.

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

Q. Is the diagnosis code set?

Troubleshoot the ETACS-ECU.

Go to Step 2.

STEP 2. Check that the headlamps operate.

Carry out the following check.

Check that the low-beam headlamps work normally.
Check that the auto lamp function work normally.
When the passing switch is operated, is the headlamp beams (high and low-beams) switched?

Q. Is the check result normal?

Go to Step 3.

Troubleshoot the headlamp.

STEP 3. M.U.T.-III other system data list.

Using the ETACS-ECU data list (Refer to

), check the automatic high beam switch signal.

When the automatic high beam switch is pressed.

Item No.	Item name	Normal condition
Item 362	AHB switch	ON

When the automatic high beam switch is not pressed.

Item No.	Item name	Normal condition
Item 362	AHB switch	OFF

OK: Normal condition is displayed.

Q. Is the check result normal?

Go to Step 4.

NO : Replace the column switch (Refer to

STEP 4. Retest the system.

Check that the automatic high beam operates 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.