Inspection Procedure K-2

Flasher Timer: Hazard Warning Lights do not Illuminate when the Hazard Warning Light Switch is Turned On.

Hazard Warning Light Circuit:

CIRCUIT OPERATION
If the ETACS-ECU receives "ON" signal from the hazard warning light switch, the ETACS-ECU turns on the flasher timer (incorporated in the ETACS-ECU), thus causing the turn-signal lights to flash.

TECHNICAL DESCRIPTION (COMMENT)
If the hazard warning lights do not flash, the power supply line to the ETACS-ECU (dedicated to the turn-signal lights) or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the hazard warning light switch
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B

STEP 1. Check the turn-signal lights.

Q: Do the turn-signal lights illuminate normally?

YES: Go to Step 2.

NO: Refer to Inspection Procedure K-1 "Turn-signal lights does not flash when the turn-signal light switch is turned on."

STEP 2. Check the input signal (by using the Pulse check mode of the monitor).
Check input signal from the hazard warning light 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.
2. Operate scan tool MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."

3. Check that scan tool MB991958 sounds when the hazard warning light switch is turned from "OFF" to "ON."

Q: Does scan tool MB991958 sound when the hazard warning light switch is turned from "OFF" to "ON"?

YES: Replace the ETACS-ECU.Check that the hazard warning lights illuminate normally.

NO: Refer to Inspection Procedure P-2 "ETACS-ECU does not receive a signal from the hazard warning light switch".