INSPECTION PROCEDURE M-1: The fog lamps do not illuminate normally.


caution Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.


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

  • Tail lamp switch
  • Headlamp switch
  • Automatic lighting switch
  • Fog lamp switch

POSSIBLE CAUSES

  • Malfunction of the column switch
  • Malfunction of the fog lamp switch
  • Malfunction of the front-ECU
  • Malfunction of the ETACS-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

Step 1. Check that the tail/stop lamps and headlamps operate.
Check that the tail/stop lamps and headlamps illuminate normally.

Q. Is the check result normal?
Go to Step 2.
Repair the tail/stop lamp(s) and headlamp(s). 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 - F.FOG LAMP
  • Ignition switch: ON
  • Lighting switch: "TAIL" or "HEAD"
  • 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 or HEAD
Item 30
 IG SW(IG1)
 ON
Item 36
 F.FOG LAMP
 ON
Item 70
 FRONT ECU ACK
 NORMAL ACK or HI-BEAM ACK
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 "Column switch (lighting and turn-signal lamp switch) signal is not received ."
Normal condition is not displayed for item No.30. : Refer to inspection procedure P-2 "The ignition switch (IG1) signal is not received ."
Normal condition is not displayed for item No.36. : Refer to inspection procedure P-3 "The fog lamp switch signal is not received ."
Normal condition is not displayed for item No.70. : Replace the front-ECU.

Step 4. Connector check: A-08X fog lamp relay connector

Q. Is the check result normal?

Go to Step 5.

Repair the defective connector.

Step 5. Check the fog lamp relay.
Refer to GROUP 54A - Fog lamp .

Q. Is the check result normal?
Go to Step 6.
Replace the fog lamp relay.

Step 6. Voltage measurement at the A-08X fog lamp relay connector.

(1)Remove the fog lamp relay, and measure at the relay box side.

(2)Check the voltage between the fog lamp relay connector and body earth.

  • Voltage between A-08X fog lamp relay connector terminal No.1 and body earth
  • Voltage between A-08X fog lamp relay connector terminal No.2 and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 8.

Go to Step 7.

Step 7. Check the wiring harness between A-08X fog lamp relay connector terminals No.1 and No.2 to the fusible link (26).


  • Check the power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

Step 8. Connector check: A-14X front-ECU connector

Q. Is the check result normal?

Go to Step 9.

Repair the defective connector.

Step 9. Check the wiring harness between A-08X fog lamp relay connector terminal No.3 to A-14X front-ECU connector terminal No.1.


  • Check the output lines for open circuit.

Q. Is the check result normal?

Go to Step 10.

Repair the wiring harness.

Step 10. Retest the system.
Check that the fog lamps illuminate normally.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.