Inspection Procedure K-4

INSPECTION PROCEDURE K-4: Front fog light: The front fog light indicator does not illuminate normally.

NOTE: This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor."

Fog Light Indicator Light Circuit:

CIRCUIT OPERATION
At the same time that the front fog lights are illuminated, the ETACS-ECU sends a signal to illuminate the front fog light indicator via the CAN bus line.

TECHNICAL DESCRIPTION (COMMENT)
If the front 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
- Trouble in input signal system
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The combination meter may be defective
- The ETACS-ECU may be defective

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- 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

- MB991813: SWS Monitor Kit
- MB991806: SWS Monitor Cartridge
- MB991812: SWS Monitor Harness (For Column-ECU)
- MB991822: Probe Harness

STEP 1. Check the front fog lights.

When the front fog light switch is operated, check that the front fog lights illuminate/go off normally.

Q: Are the front fog lights operating properly?

YES: Go to Step 2.

NO: First, repair the front fog lights. Refer to Inspection Procedure K-3 "One of the front fog lights does not illuminate."

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 SWS monitor."
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 (Refer to Information Bus, Diagnosis).

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.

NO: Go to Step 4.

STEP 4. Use scan tool MB991958 to select "ECU COMM Check" on the SWS monitor display.

Check the ETACS-ECU.

CAUTION: Connect special tool MB991910 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.







1. Connect the SWS monitor. Refer to "How to connect SWS monitor."
2. Turn the ignition switch to the "ON" position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."

4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" menu for the "ETACS ECU" menu.

Q: Is "OK" displayed for the "ETACS ECU" menu?

YES: Go to Step 5.

NO: Refer to Inspection Procedure A-3 "Communication with the ETACS-ECU is not possible."

STEP 5. Replace the combination meter.

1. Replace the combination meter.
2. Check that the front fog light indicator light illuminates normally.

Q: Is the front fog light indicator light operating properly?

YES: No action is necessary and testing is complete.

NO: Replace the ETACS-ECU. When the ETACS-ECU is replaced, register the encrypted code. Refer to Encrypted Code Registration Criteria Table in Antitheft and Alarm Systems. Check that the front fog light indicator light illuminates normally.