Inspection Procedure
4: 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.
PROBABLE CAUSES
Malfunction of the fog lamp switch
Malfunction of the ETACS-ECU
Damaged harness wires and connectors
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 Table ).
(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.
Turn the rear fog lamp switch to ON.
Item No.
Item name
Normal condition
Item 231
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 11 "The column switch
signal is not received" .
STEP 5. Connector check: F-21 rear fog lamp connector <LH
drive vehicles>
or F-11 rear fog lamp connector <RH drive vehicles>
Q.
Is the check result normal?
Go to Step 6.
Repair the defective connector.
STEP 6. Check the bulb of the rear fog lamp
Check the bulb of the defective lamp.
Q.
Is the check result normal?
Go to Step 7.
Replace the bulb of the defective lamp.
STEP 7. Resistance measurement at the F-21 rear fog lamp connector <LH
drive vehicles>
or F-11 rear fog lamp connector <RH drive vehicles>
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Check the resistance between the lamp connector and body earth.
Resistance between F-21 rear fog lamp connector <LH
drive vehicles>
or F-11 rear fog lamp connector <RH drive vehicles>
connector
terminal No.1 and body earth
OK: Continuity exists (2 Ω
or less)
Q.
Is the check result normal?
Go to Step 9.
Go to Step 8.
STEP 8. Wiring harness check between the F-21 rear fog lamp connector <LH
drive vehicles>
or F-11 rear fog lamp connector <RH drive vehicles>
terminal
No. 1 and the body earth
note
Before the wiring harness check, check the intermediate connector F-19 and F-22, and then repair
that if necessary.
STEP 10. Wiring harness check between the F-21 rear fog lamp connector <LH
drive vehicles>
or F-11 rear fog lamp connector <RH drive vehicles>
terminal
No. 2 and the C-311 ETACS-ECU connector terminal No. 14
note
Before the wiring harness check, check the intermediate connector F-19 and F-22, and then repair
that 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 ).
)
)
)
)
).
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.