Inspection Procedure 5

Inspection Procedure 5: The Headlight Automatic Leveling Warning Light Does Not Go Off.

CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

TECHNICAL DESCRIPTION (COMMENT)
If the headlight automatic leveling warning display does not go off, DTC may be set, or the automatic leveling ECU or the combination meter may have a problem.

TROUBLESHOOTING HINTS
- Diagnostic trouble code setting is under way.
- Malfunction of the headlight automatic leveling-ECU
- Malfunction of combination meter
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

STEP 1. Using scan tool MB991958, read the diagnostic trouble code.

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)." Scan Tool Connecting
2. Turn the ignition switch to the "ON" position.
3. Check whether the headlight automatic leveling-ECU related DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is DTC set?

YES : Perform the troubleshooting of when the diagnostic trouble code is set. Diagnostic Trouble Code Descriptions

NO : Go to Step 2.

STEP 2. Using scan tool MB991958, check other system actuator test.

Perform the actuator test for the combination meter, and check that the headlight automatic leveling warning is displayed.

1. Turn the ignition switch to the "ON" position.
2. Set scan tool MB991958 to the actuator test mode.
- Item 8: Indicator2

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

Q: Is the check result normal?

YES : Go to Step 3.

NO : Replace the combination meter.

STEP 3. Retest the system.

Check whether the headlight automatic leveling warning display goes out.

Q: Is the check result normal?

YES : The trouble can be an intermittent malfunction (Refer to general (body and chassis) - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).

NO : Replace the headlight automatic leveling-ECU.