Inspection Procedure 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



PROBABLE CAUSES



  • Malfunction of the headlamp bulbs
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-13 headlamp assembly (LH) connector, A-26 headlamp assembly (RH) connector

Q. Is the check result normal?
Go to Step 2.
Repair the defective connector.

STEP 2. Bulb check
Check the bulb(s) of headlamp that does not illuminate.

Q. Is the check result normal?
Go to Step 3.
Replace the bulb(s) of the lamp that does not illuminate.

STEP 3. Resistance measurement at the A-13 headlamp assembly (LH) connector, A-26 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 A-13 headlamp assembly (LH) connector terminal No.10 and the body earth.
  • Measure the resistance between the A-26 headlamp assembly (RH) connector terminal No.10 and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 5.
Go to Step 4.

STEP 4. Check the wiring harness from A-13 headlamp assembly (LH) connector terminal No.10 or A-26 headlamp assembly (RH) connector terminal No.10 to body earth
note Prior to the wiring harness inspection, check the earth connector B-102 and repair if necessary. <LHD>

  • 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 Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the wiring harness.

STEP 5. Check the wiring harness from A-13 headlamp assembly (LH) connector terminal No.1 or 4 or A-26 headlamp assembly (RH) connector terminal No.1 or 4 to A-05X headlamp relay (LO) or A-04X headlamp relay (HI) connector terminal No.4.

  • Check the power supply line for open circuit and short circuit.

Q. Is the check result normal?
Go to Step 6.
Repair the wiring harness.

STEP 6. 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.