Inspection Procedure J-4

Headlight, Taillight: When the passing switch is turned "on", the headlights (low-beam or high-beam) do not illuminate.

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." How To Use SWS Monitor

TECHNICAL DESCRIPTION (COMMENT)
If both of the headlights (low-beam and high-beam) do not illuminate, the input circuit from the passing switch or the front-ECU may be defective.

TROUBLE SHOOTING HINTS
- The column switch may be defective
- The front-ECU may be defective
- The wiring harness or connections may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A
- MB991813: SWS monitor kit
- MB991806: SWS Monitor Cartridge
- MB991812: SWS Monitor Harness (For Column-ECU)
- MB991822: Probe Harness
- MB991854: SWS Monitor Harness (For 13-pin)

STEP 1. Verify the headlight operation.

Q: Do the headlights (low-beam and high-beam) illuminate normally?

YES : Go to Step 2.

NO : Refer to Inspection Procedure J-2 "Headlights (low-beam) do not illuminate normally."

NO : Refer to Inspection Procedure J-3 "Headlights (high-beam) do not illuminate normally."

STEP 2. Check the input signal by using "DATA LIST" menu of the SWS monitor.

Turn the passing switch to the "ON" position before checking input signals from the passing switch.

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 to the data link connector (16-pin).
2. Connect SWS monitor harness MB991854 to the data link connector (13-pin).
3. Operate the scan tool MB991958 according to the procedure below to display "COLUMN ECU."
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "DATA LIST"
e. Select "COLUMN ECU"




4. Check that normal conditions are displayed on the items described in the table.

Q: Is normal condition displayed on the "PASSING SW"?

YES: Replace the front-ECU. When the passing switch is turned "ON", the headlights (low-beam and high-beam) should illuminate normally.

NO: Refer to Inspection Procedure N-6 "ETACS-ECU does not receive a signal from the passing switch."