Inspection Procedure 3: The rear fog lamp 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 rear fog lamp do not illuminate, the wiring harness connector(s), the bulb or the fuse may be defective. Otherwise the input signal circuit(s) below or the ETACS-ECU may be defective.

  • Tail lamp switch
  • Headlamp switch
  • Rear fog lamp switch

PROBABLE CAUSES

  • Malfunction of the column switch
  • Malfunction of the rear fog lamp relay
  • Burned-out rear fog lamp bulb
  • Malfunction of the ETACS-ECU
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check that the rear fog lamp indicator operate.
Check that the rear fog lamp indicator illuminates.

Q. Does the rear fog lamp indicator illuminate?
Go to Step 12
Go to Step 2

STEP 2. 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 3
Repair the tail/stop lamp(s) and headlamp(s). Refer to trouble symptom chart .

STEP 3. M.U.T.-III diagnosis code.
When the electric motor switch is turned to the "LOCK" (OFF) position, check that the ETACS-ECU does not set the diagnosis code.

Q. Is the diagnosis code set?
Refer to diagnosis code chart .
Go to Step 4

STEP 4. M.U.T.-III data list
Check the input signals below, which are related to the rear fog lamp.

  • Turn the electric motor switch to the "LOCK" (OFF) position.
  • Turn the tail lamp switch to the ON position.
  • Turn the rear fog lamp switch to the ON position.
Item No.
 Item name
 Normal condition
30
 IG SW (IG1) /Power SW(ON)
 OFF
71
 Rear fog lamp
 ON
OK: Normal conditions are displayed for all the items

Q. Are the check result normal?
YES <All the signals are received normally.> : Go to Step 5
NO <The electric motor switch (IG1) signal is not received.> : Refer to inspection procedure 2 "The electric motor switch (IG1) signal is not received ."
NO <The rear fog lamp switch signal is not received.> : Refer to inspection procedure 9 "The column switch signal is not received ."

STEP 5. Connector check: B-312 rear fog lamp relay connector

Q. Is the check result normal?
Go to Step 6
Repair the defective connector.

STEP 6. Check the rear fog lamp relay.
Refer to .

Q. Is the check result normal?
Go to Step 7
Replace the rear fog lamp relay.

STEP 7. Voltage measurement at the B-312 rear fog lamp relay connector.
(1)Remove the rear fog lamp relay, and measure at the junction block side.
(2)Check the voltage between the rear fog lamp relay connector and body earth.

  • Voltage between B-312 rear fog lamp relay connector terminal No.1 and body earth
  • Voltage between B-312 rear fog lamp relay connector terminal No.4 and body earth
OK: System voltage

Q. Is the check result normal?
Go to Step 9
Go to Step 8

STEP 8. Check the wiring harness between B-312 rear fog lamp relay connector terminals No.1, 4 and the fusible link (25).
note Prior to the wiring harness inspection, check junction block connector B-310, and repair if necessary.

  • Check the power supply line for open circuit and short circuit.

Q. Is the check result normal?
Go to Step 11
Repair the wiring harness.

STEP 9. Connector check: B-318 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 10
Repair the defective connector.

STEP 10. Check the wiring harness between B-312 rear fog lamp relay connector terminal No.2 and B-318 ETACS-ECU connector terminal No.32.
note Prior to the wiring harness inspection, check junction block connector B-303, and repair if necessary.

  • Check the output lines for open circuit.

Q. Is the check result normal?
Go to Step 11
Repair the wiring harness.

STEP 11. 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 and register the ID codes (Refer to ).

STEP 12. Connector check: E-08 rear fog lamp connector

Q. Is the check result normal?
Go to Step 13
Repair the defective connector.

STEP 13. Check the bulbs of the rear fog lamps lamp.
Check the bulb(s) of the defective lamp.

Q. Is the check result normal?
Go to Step 14
Replace the bulb(s) of the defective lamp.

STEP 14. Resistance measurement at the E-08 rear fog lamp connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Check the resistance between the lamp connector and body earth.

  • Resistance between E-08 rear fog lamp connector terminal No.2 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 16
Go to Step 15

STEP 15. Check the wiring harness from E-08 rear fog lamp connector terminal No.2 to body earth.
note Prior to the wiring harness inspection, check earth connector C-104, and repair if necessary.

  • Check the earth wires for open circuit.

Q. Is the check result normal?
Go to Step 18
Repair the wiring harness.

STEP 16. Connector check: Connector check: E-08 rear fog lamp relay connector

Q. Is the check result normal?
Go to Step 17
Repair the defective connector.

STEP 17. Check the wiring harness from E-08 rear fog lamp connector terminal No.1 to B-312 rear fog lamp relay connector terminal No.3.
note Prior to the wiring harness inspection, check intermediate connector C-102 and junction block connector B-319, and repair if necessary.

  • Check the power supply line for open circuit.

Q. Is the check result normal?
Go to Step 18
Repair the wiring harness.

STEP 18. 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 rear fog lamp.