Inspection Procedure 3

Inspection Procedure 3: THe Front Fog Light Indicator Does Not Illuminate Normally.

CAUTION: Whenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

Front Fog Light Indicator Light Circuit:

TECHNICAL DESCRIPTION (COMMENT)
If the fog light indicator does not illuminate normally, connector(s), wiring harness in the CAN bus lines, the ETACS-ECU or the combination meter may be defective.

TROUBLESHOOTING HINTS
- The ETACS-ECU may be defective
- The combination meter may be defective
- Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Check the fog lights.
When the fog light switch is operated, check that the fog lights illuminate and go off normally.

Q: Is the fog lights normal?

YES : Go to Step 2.

NO : First, repair the front fog lights. Refer to Inspection Procedure 2 "One of the fog lights does not illuminate." Inspection Procedure 2

STEP 2. Using scan tool MB991958, diagnose the CAN bus line.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.







1. Connect scan tool MB991958. Refer to "How to connect scan tool (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 3.

NO : Repair the CAN bus line.

STEP 3. Using scan tool MB991958, read the combination meter diagnostic trouble code.

1. Check whether a combination meter-related DTC is set.
2. Turn the ignition switch to the "ON" position.
- Check whether the combination meter-related DTC is set.

3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Diagnose the combination meter (Refer to combination meter, Diagnosis). Diagnostic Trouble Code Descriptions

NO : Go to Step 4.

STEP 4. Using scan tool MB991958, check actuator test.

1. Turn the ignition switch to the "ON" position.
2. Perform the actuator test for the combination meter, and check that the fog light indicator illuminates (Refer to combination meter, Diagnosis). Symptom Chart
3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the check result normal?

YES : Replace the ETACS-ECU.

NO : Replace the combination meter.