Inspection Procedure A-4: One of the headlamps does not illuminate.


caution Whenever the ECU is replaced, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM


When one of the headlamps does not illuminate, the wiring harness, connector(s), or the bulb may have a problem, or the fuse may be burned out.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Bulb check
Check the bulb(s) of headlamp that does not illuminate.

Q. Is the check result normal?
Go to Step 2.
Replace the bulb(s) of the lamp that does not illuminate (Refer to ).

STEP 2. Resistance measurement at the headlamp assembly (LH) connector, headlamp assembly (RH) connector
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the connector of lamp which does not illuminate and the body earth.

  • Measure the resistance between the headlamp assembly (LH) connector (E terminal) and the body earth.
  • Measure the resistance between the headlamp assembly (RH) connector (E terminal) and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 4.
Go to Step 3.

STEP 3. Check of open circuit in body E line between headlamp assembly (LH) connector or headlamp assembly (RH) connector and body earth.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.

STEP 4. Check of short to power supply, and open circuit in COML line between headlamp assembly (LH) connector or headlamp assembly (RH) connector and headlamp relay (LO) connector.

Q. Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.

STEP 5. Retest the system
Check that the headlamps illuminate normally.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the headlamp socket (Refer to ).