Inspection Procedure O-4

INSPECTION PROCEDURE O-4: The hazard warning light switch signal is not sent to the ETACS-ECU.




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
- The hazard warning light switch may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

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 : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. 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 ground circuit to the hazard warning light switch. Test at hazard warning light switch connector C-09.




1. Disconnect the hazard warning light switch connector C-09 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance between terminal 2 and ground.
- The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 5.

NO : Go to Step 3.




STEP 3. Check the hazard warning light switch connector C-09 for loose, corroded or damaged terminals, or terminals pushed back in the
connector.

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

YES : Go to Step 4.

NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Diagnostic Aids 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 wiring harness between hazard warning light switch connector C-09 (terminal 2 and ground.

Q: Is the wiring harness between hazard warning light switch connector C-09 (terminal 2) and ground in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. 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-318 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are hazard warning light switch connector C-09 and ETACS-ECU connector C-318 in good condition?

YES : Go to Step 6.

NO : Repair or replace the damaged component(s). 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 wiring harness between hazard warning light switch connector C-09 (terminal 1) and ETACS-ECU connector C-318 (terminal 55).

Q: Is the wiring harness between hazard warning light switch connector C-09 (terminal 1) and ETACS-ECU connector C-318 (terminal 55) 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 : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. 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.