Inspection Procedure J-5: The front fog lamp switch signal is not received.


caution Whenever the ECU is replaced, ensure that the input signal circuit is normal.


COMMENTS ON TROUBLE SYMPTOM


Input signal from the front fog lamp switch is used to operate the front fog lamps. If the signal is abnormal, the front fog lamps will not illuminate and extinguish normally.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-18 fog lamp switch connector


Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

STEP 2. Check the fog lamp switch.
Refer to GROUP 54A - fog lamp .

Q. Is the check result normal?
Go to Step 3.
Replace the fog lamp switch.

STEP 3. Resistance measurement at the B-18 fog lamp switch connector.


(1)Remove the fog lamp switch, and measure at the wiring harness side.

(2)Resistance between B-18 fog lamp switch connector terminal No.6 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

STEP 4. Check the wiring harness from B-18 fog lamp switch connector terminal No.6 to body earth.



  • Check the earth wires for open circuit.

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 ).

Repair the wiring harness.

STEP 5. Connector check: B-233 ETACS-ECU connector


Q. Is the check result normal?

Go to Step 6.

Repair the defective connector.

STEP 6. Check the wiring harness from B-233 ETACS-ECU connector No.58 to B-18 fog lamp switch connector terminal No.5.





  • Check the input line for open circuit and short circuit.

Q. Is the check result normal?

Go to Step 7.

Repair the wiring harness.

STEP 7. M.U.T.-III data list
Check the input signals from the front fog lamp switch.

  • Operate the front fog lamp switch.
Item No.
 Item name
 Normal condition
23
 Front fog lamp switch
 ON
OK: Normal condition is displayed.

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. Then perform the variant coding and write the VIN data (Refer to GROUP 00, Precautions Before Service - How to Perform Variant Coding ).