Inspection Procedure O-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 described in "CIRCUIT OPERATION" do network normally.

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

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe




STEP 1. Check hazard warning light switch connector C-03 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

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

YES: Go to Step 2.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. If the equipment described in "CIRCUIT OPERATION" works normally, the input signal from the hazard warning light switch should be normal.







STEP 2. Check the hazard warning light switch.
Remove the hazard warning light switch. Then check continuity between the switch terminals.

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

YES: Go to Step 3.

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

STEP 3. Check the ground circuit to the hazard warning light switch. Measure the resistance at hazard warning light switch connector C-03.




1. Disconnect hazard warning light switch connector C-03 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance value 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 4.







STEP 4. Check the wiring harness between hazard warning light switch connector C-03 (terminal 2) and ground.

NOTE: Also check joint connector C-06 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-06 is damaged, repair or replace the damaged components) as described in Harness Connector Inspection.

Q: Is the wiring harness between hazard warning light switch connector C-03 (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. If the equipment described in "CIRCUIT OPERATION" works normally, the input signal from the hazard warning light switch should be normal.




STEP 5. Check ETACS-ECU connector C-228 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-228 in good condition?

YES: Go to Step 6.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. If the equipment described in "CIRCUIT OPERATION" works 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 (terminal 1) and ETACS-ECU connector C-228 (terminal 55).

Q: Is the wiring harness between hazard warning light switch connector C-03 (terminal 1) and ETACS-ECU connector C-228 (terminal 55) in good condition?

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

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. If the equipment described in "CIRCUIT OPERATION" works normally, the input signal from the hazard warning light switch should be normal.