Step 1. Check that the headlamps operate.

Check that the headlamps illuminate normally.

Q: Is the check result normal?

YES:  Go to Step 2.
NO:  Check the tail lamps and the headlamps (Refer to trouble symptom chart ).

Step 2. ECU check by using the SWS monitor

Check that the power supply and earth lines to the column switch (column-ECU), the ETACS-ECU and the front-ECU and the SWS communication lines are normal.

• Ignition switch: OFF

ECUS TO BE CHECKED

• COLUMN ECU

• ETACS ECU

• FRONT ECU

OK: "OK" are displayed for all the items

Q: Are the check result normal?

"OK" are displayed for all the items:  Go to Step 3.
"NG" is displayed on the "COLUMN ECU" menu.:  Refer to Inspection Procedure A-2 "Communication with the column switch (column-ECU) is not possible ."
"NG" is displayed on the "ETACS ECU" menu.:  Refer to Inspection Procedure A-3 "Communication with the ETACS-ECU is not possible ."
"NG" is displayed on the "FRONT ECU" menu.:  Refer to Inspection Procedure A-4 "Communication with the front-ECU is not possible ."

Step 3. Function diagnosis by using the SWS monitor

Check the SWS communication signal, which are related to the fog lamps.

<Selected item> LIGHTING - REAR FOG LAMP

• Ignition switch: ON

• Lighting switch: "TAIL" or "HEAD"

• Rear fog lamp switch: ON

Item No.	Item name	Normal condition
Item 00	HEADLAMP SW	ON when the lighting switch is at HEAD
Item 01	TAIL LAMP SW	ON when the lighting switch is at TAIL

OK: Normal conditions are displayed for all the items.

Q: Are the check result normal?

Normal conditions are displayed for all the items.:  Go to Step 4.
Normal condition is not displayed for item 00 or 01.:  Refer to inspection procedure P-5 "The column switch (lighting and turn-signal lamp switch) signal is not received ."

Step 4. Pulse check

Check the input signals below, which are related to the rear fog lamps.

System switch	Check condition
Ignition switch (IG1)	When turned from ACC to ON
Rear fog lamp switch	When the rear fog lamp switch is turned from off to on

OK: The MUT-II/III sounds or the voltmeter needle fluctuates.

Q: Are the check result normal?

All the signals are received normally.:  Go to Step 5.
The ignition switch (IG1) signal is not received.:  Refer to inspection procedure P-2 "The ignition switch (IG1) signal is not received ."
The rear fog lamp switch signal is not received.:  Refer to inspection procedure P-19 "The rear fog lamp switch signal is not received ."

Step 5. Connector check: C-35 rear fog lamp-ECU connector

Q: Is the check result normal?

YES:  Go to Step 6.
NO:  Repair the defective connector.

Step 6. Check the rear fog lamp-ECU.

Refer to GROUP 54A - Rear fog lamp .
YES:  Go to Step 7.
NO:  Replace the rear fog lamp-ECU.

Step 7. Voltage measurement at the C-35 rear fog lamp-ECU connector.

1. Remove the rear fog lamp-ECU, and measure at the harness side.

2. Check the voltage between the rear fog lamp-ECU connector and body earth.
• Voltage between C-35 rear fog lamp-ECU connector terminal No.4 and body earth
OK: System voltage

Q: Is the check result normal?

YES:  Go to Step 9.
NO:  Go to Step 8.

Step 8. Check the wiring harness between C-35 rear fog lamp-ECU connector terminal No4 and the fusible link (1).

NOTE: Prior to the wiring harness inspection, check intermediate connectors A-14, C-125 and junction block connector C-204, and repair if necessary.

• Check the power supply line for open circuit.

Q: Is the check result normal?

YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Repair the wiring harness.

Step 9. Measure the resistance at the C-35 rear fog lamp-ECU connector.

1. Remove the rear fog lamp-ECU, and measure at the wiring harness.

2. Continuity between C-35 rear fog lamp-ECU connector terminal No.8 and body earth
OK: 2Ω or less

Q: Is the check result normal?

YES:  Go to Step 11.
NO:  Go to Step 10.

Step 10. Check the wiring harness between C-35 rear for lamp-ECU connector terminal No.8 and body earth.

• Check the earth wires for open circuit.

Q: Is the check result normal?

YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Repair the wiring harness.

Step 11. Connector check: C-219 ETACS-ECU connector

Q: Is the check result normal?

YES:  Go to Step 12.
NO:  Repair the defective connector.

Step 12. Check the wiring harness between C-35 rear fog lamp-ECU connector terminal No7 and C-219 ETACS-ECU connector terminal No.59.

NOTE: Prior to the wiring harness inspection, check joint connector C-02, and repair if necessary.

• Check the output lines for open circuit.

Q: Is the check result normal?

YES:  Go to Step 13.
NO:  Repair the wiring harness.

Step 13. Retest the system.

Check that the rear fog lamps illuminate normally.

Q: Is the check result normal?

YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Replace the ETACS-ECU.