Inspection Procedure P-11: The hazard warning lamp switch signal is not received.


caution Whenever the ECU is replaced, ensure that the input signal circuit is normal.


COMMENTS ON TROUBLE SYMPTOM
Input signal from the hazard warning lamp switch is used to operate the functions below. If the signal is abnormal, these functions will not work normally.

  • Keyless entry system (encrypted code registration)
  • Hazard warning lamp

POSSIBLE CAUSES

  • Malfunction of the hazard warning lamp switch
  • Malfunction of the ETACS-ECU
  • Damaged harness wires and connectors

DIAGNOSTIC PROCEDURE

Step 1. Connector check: C-123 hazard warning lamp switch connector

Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

Step 2. Check the hazard warning lamp switch.
Refer to GROUP 54A - Hazard warning lamp switch .

Q. Is the check result normal?
Go to Step 3.
Replace the hazard warning lamp switch.

Step 3. Resistance measurement at the C-123 hazard warning lamp switch connector.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Resistance between C-123 hazard warning lamp switch connector terminal No.2 and body earth
OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

Step 4. Check the wiring harness between C-123 hazard warning lamp switch connector terminal No.2 to the body earth.


  • Check the earth wires for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

Step 5. Connector check: C-221 ETACS-ECU connector

Q. Is the check result normal?

Go to Step 6.

Repair the defective connector.

Step 6. Check the wiring harness between C-221 ETACS-ECU connector terminal No.55 to C-123 hazard warning lamp switch connector terminal No.1.



  • Check the input line for open circuit.

Q. Is the check result normal?

Go to Step 7.

Repair the wiring harness.

Step 7. Retest the system.
Check that the hazard warning lamp switch signal is received normally.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.