Inspection Procedure 6

Inspection Procedure 6: High-Beam Indicator Light 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.

High-Beam Indicator Light Circuit:

TECHNICAL DESCRIPTION (COMMENT)
If the high-beam indicator does not illuminate normally, the harness in the CAN bus lines, connector(s), ETACS-ECU, or combination meter may have a problem.

TROUBLESHOOTING HINTS
- Malfunction of the ETACS-ECU
- Malfunction of combination meter
- Damaged harness wires and connectors

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. Check of headlight (high-beam).
Check that the headlights (high-beam) illuminate/extinguish normally when the lighting switch is operated.

Q: Is the check result normal?

YES : Go to Step 2.

NO : Refer to Inspection Procedure 2 "None of headlights (high-beam) illuminates." 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 the Scan Tool (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch from "LOCK" (OFF) position to "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 ETACS-ECU diagnostic trouble code.

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. Check whether the ETACS-ECU related DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Diagnose the ETACS-ECU. Refer to ETACS, 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 high-beam indicator light illuminates (Refer to combination meter. Actuator Test Table
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.