Inspection Procedure 5: One of the headlamps does not illuminate. <4-bulb type>


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-58 <headlamp (LO: LH)>, A-147 <headlamp (LO: RH)>, A-59 (HI: LH), A-146 (HI: RH) headlamp 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-58 <headlamp (LO: LH)>, A-147 <headlamp (LO: RH)>, A-59 (HI: LH), A-146 (HI: RH) headlamp 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-58 headlamp (LO: LH) connector terminal No. 1 and the body earth.
  • Measure the resistance between the A-147 headlamp (LO: RH) connector terminal No. 1 and the body earth.
  • Measure the resistance between the A-59 headlamp (HI: LH) connector terminal No. 1 and the body earth.
  • Measure the resistance between the A-146 headlamp (HI: RH) connector terminal No. 1 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-58 <headlamp (LO: LH)>, A-147 <headlamp (LO: RH)>, A-59 (HI: LH), A-146 (HI: RH) headlamp connector (terminal No.1) to 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 Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 5. Check the wiring harness from A-58 <headlamp (LO: LH)>, A-147 <headlamp (LO: RH)>, A-59 (HI: LH), A-146 (HI: RH) headlamp connector (terminal No.2) to A-22X headlamp relay (LO) or A-23X headlamp relay (HI) connector (terminal No.3)




  • 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.