Inspection Procedure 1

Inspection Procedure 1: None of taillights illuminates.

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

TECHNICAL DESCRIPTION (COMMENT)

If none of taillights illuminates, the taillight switch input circuit or ETACS-ECU may have a problem.

TROUBLESHOOTING HINTS

- Malfunction of column switch
- Malfunction of the ETACS-ECU
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

STEP 1. License plate light operation check

Check that the license plate light illuminates normally.

Q. Does license plate light work normally?

YES Go to Step 2.
NO Replace the ETACS-ECU.
STEP 2. Using scan tool MB991958, read the diagnostic trouble code.

(1)
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.

Connect scan tool MB991958. Refer to "How to connect scan too (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."

(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 Electronic Time and Alarm Control System (ETACS).
NO Go to Step 3.
STEP 3. Using scan tool MB991958, check data list.

Use the ETACS-ECU data list to check the signals related to the taillight illumination.

- Turn the taillight switch to the "ON" position.





Q. Does scan tool MB991958 display the items "Taillight" as normal condition?

YES Go to Step 4.
NO Troubleshoot the ETACS-ECU (Refer to Symptom Chart).
STEP 4. Retest the system

Check that the taillight illuminates normally.

Q. Does the taillight work normally?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Replace the ETACS-ECU.