Inspection Procedure M-2

The ETACS-ECU does not Receive Any Signal from the Hazard Warning Light Switch

Hazard Warning Light Switch Input Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates the following functions or systems according to signal from the hazard warning light switch:
- Hazard warning light
- Keyless entry system (registering the encrypted code)

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the equipment or systems, which are described in "CIRCUIT OPERATION", do 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)







STEP 1. Check the hazard warning light switch.

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

YES: Go to Step 2.

NO: Replace the hazard warning light switch. If the equipment, which are described in "CIRCUIT OPERATION", work normally, the input signal from the hazard warning light switch should be normal.




STEP 2. Measure at hazard warning light switch connector C-03 in order to check the ground circuit to the hazard warning light switch.

1. Disconnect hazard warning light switch connector C-03, and measure at the wiring harness side.
2. Measure the resistance value between terminal 2 and ground.
- The measured value should be 2 Ohm or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 5.

NO: Go to Step 3.




STEP 3. Check hazard warning light switch connector C-03 for damage.

Q: Is hazard warning light switch connector C-03 in good condition?

YES: Go to Step 4.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the equipment, which are described in "CIRCUIT OPERATION", work normally, the input signal from the hazard warning light switch should be normal.




STEP 4. Check the wiring harness between hazard warning light switch connector C-03 and ground.

NOTE: Also check joint connector C-06. If joint connector C-06 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between hazard warning light switch connector C-03 and ground in good condition?

YES: No action to be taken.

NO: Repair the wiring harness. If the equipment, which are described in "CIRCUIT OPERATION", work normally, the input signal from the hazard warning light switch should be normal.







STEP 5. Check hazard warning light switch connector C-03 and ETACS-ECU connector C-228 for damage.

Q: Are hazard warning light switch connector C-03 and ETACS-ECU connector C-228 in good condition?

YES: Go to Step 6.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the equipment, which are described in "CIRCUIT OPERATION", work normally, the input signal from the hazard warning light switch should be normal.







STEP 6. Check the wiring harness between hazard warning light switch connector C-03 and ETACS-ECU connector C-228.

Q: Is the wiring harness between hazard warning light switch connector C-03 and ETACS-ECU connector C-228 in good condition?

YES: Replace the ETACS-ECU. If the equipment, which are described in "CIRCUIT OPERATION", work normally, the input signal from the hazard warning light switch should be normal.

NO: Repair the wiring harness. If the equipment, which are described in "CIRCUIT OPERATION", work normally, the input signal from the hazard warning light switch should be normal.