Inspection Procedure O-4

The hazard warning light switch signal is not sent to the ETACS-
ECU.

Hazard Warning Light Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates various functions according to the input signal from the hazard warning light switch.

TECHNICAL DESCRIPTION (COMMENT)
Hazard warning light switch input signal is used to operate the following device or system:
- Hazard warning light
- Keyless entry system (registering the encrypted code)

If the signal fails, these device or system will not work normally.

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

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness







STEP 1. Check the hazard warning light switch.

Q: Is the hazard warning light switch in good condition?

YES: Go to Step 2.
NO: Repair it. The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

STEP 2. Check the hazard warning light switch ground circuit at the hazard warning light switch connector C-09.
1. Disconnect the hazard warning light switch connector C-09 and measure at the harness side.




2. Measure the resistance between terminal 2 and ground.

Q: Is the resistance less than 2 ohm?

YES: Go to Step 5.
NO: Go to Step 3.




STEP 3. Check hazard warning light switch connector C-09 for damage.

Q: Is hazard warning light switch connector C-09 in good condition?

YES: Go to Step 4.
NO: Repair or replace it. Refer to Harness Connector Inspection. The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.




STEP 4. Check the harness wire between hazard warning light switch connector C-09 and ground.

Q: Is the harness wire between hazard warning light switch connector C-09 and ground in good condition?

YES: There is no action to be taken.
NO: Repair it. The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.







STEP 5. Check the hazard warning light switch connector C-09 and ETACS-ECU connector C-313 for damage.

Q: Are hazard warning light switch connector C-09 and ETACS-ECU connector C-313 in good condition?

YES: Go to Step 6.
NO: Repair or replace them. Refer to Harness Connector Inspection. The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.







STEP 6. Check the harness wire between hazard warning light switch connector C-09 and ETACS-ECU connector C-313.

Q: Is the harness wire between hazard warning light switch connector C-09 and ETACS-ECU connector C-313 in good condition?

YES: Replace the ETACS-ECU. The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.
NO: Repair it. The hazard warning light switch input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.