Inspection Procedure 1: The rear fog lamp do not illuminate normally.



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

CIRCUIT OPERATION


If the rear fog lamps do not illuminate normally, the input signal circuit(s) below or the ETACS-ECU may be defective.


COMMENTS ON TROUBLE SYMPTOM


When the rear fog lamps do not illuminate normally, the mentioned input signal circuit(s) or ETACS-ECU may be defective.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. ETACS-ECU coding data check


(1)Operate the M.U.T.-III to read the ETACS-ECU option coding information (Refer to GROUP 00 - Coding List <Vehicles for General Export>, <Vehicles for GCC>, <Vehicles for Thailand>).
(2)Check that the "Rear fog lamp" is set to "Present."

Q. Is the check result normal?

Go to Step 2.

Operate the M.U.T.-III to set the option coding "Rear fog lamp" to "Present," and check the trouble symptom.

STEP 2. Check the operation of the position lamps and the headlamps.


Check that the position lamps and the headlamps illuminate normally.

Q. Is the check result normal?

Go to Step 3.

Check the position lamps and the headlamps (Refer to trouble symptom chart ).

STEP 3. 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 4.

STEP 4. M.U.T.-III data list


Use the ETACS-ECU service data to check the signal related to the operation of rear fog lamp function.

Item No.
Item name
Normal condition
71
Rear fog lamp
ON
OK: Normal condition is displayed.

Q. Is the check result normal?

Go to Step 5.

Troubleshoot the ETACS-ECU. Refer to Inspection Procedure 9 "The column switch signal is not received" .

STEP 5. Check the bulb of the rear fog lamp


Check the bulb of the defective lamp.

Q. Is the check result normal?

Go to Step 6.

Replace the bulb of the defective lamp.

STEP 6. Resistance measurement at the rear combination lamp (rear fog) connector (earth terminal).


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the rear combination lamp (rear fog) connector (earth terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 8.

Go to Step 7.

STEP 7. Check of open circuit in earth line between the rear combination lamp (rear fog) connector and body earth.


Q. Is the check result normal?

Go to Step 8.

Repair the connector(s) or wiring harness.

STEP 8. Check of open circuit in RFOG line between the rear combination lamp (rear fog) connector and ETACS-ECU connector.


Q. Is the check result normal?

Go to Step 9.

Repair the connector(s) or wiring harness.

STEP 9. Retest the system


Check that the rear fog lamp illuminate 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.