Inspection Procedure 1

Inspection Procedure 1: The hazard warning lights do not illuminate.

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 hazard warning light does not illuminate, the hazard warning light switch input circuit in center panel unit or the ETACS-ECU may have a problem.

TROUBLESHOOTING HINTS

- Malfunction of center panel unit
- 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. Check that the turn-signal light operate.

Check that the turn-signal lights illuminate normally.

Q. Does turn-signal light work normally?

YES Go to Step 2.
NO Diagnose the headlights. Refer to Inspection Procedure 11 "None of turn-signal lights illuminates" Inspection Procedure 11.
STEP 2. Using scan tool MB991958, check data list.

Using the ETACS-ECU service data, check the hazard warning light signal.

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) Reading and Clearing Diagnostic Trouble Codes."
2. Turn the ignition switch to the "ACC" position.
3. Turn "ON" the hazard light switch.






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

YES (Normal condition is displayed for item) Go to Step 3.
NO (Normal condition is not displayed for item No. 265.) Troubleshoot the ETACS-ECU.
Refer to ETACS, Diagnosis - Inspection Procedure 10 "ETACS-ECU does not receive any signal from the hazard warning light switch" Inspection Procedure 10.
STEP 3. Retest the system

Check that the hazard warning light illuminate 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.