Inspection Procedure 2: The High-beam Headlamps do not Illuminate Normally.

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

If both headlamps (high-beam) do not illuminate normally, the head lamp switch input circuit, headlamp relay (HI), or ETACS-ECU may have a problem.

PROBABLE CAUSES

Malfunction of column switch
Malfunction of headlamp relay (HI)
Malfunction of the ETACS-ECU
Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Check if diagnosis code is set to the ETACS-ECU.

Q. Is the diagnosis code set?

Troubleshoot the ETACS-ECU. Refer to

Go to Step 2.

STEP 2. Connector check: A-20X headlamp relay (HI) connector

Q. Is the check result normal?

Go to Step 3.

Repair the defective connector.

STEP 3. Headlamp relay (HI) check

Refer to

Q. Is the check result normal?

Go to Step 4.

Replace the headlamp relay (HI).

STEP 4. Voltage measurement at the A-20X headlamp relay (HI) connector

(1)Remove the headlamp relay (HI), and measure at the relay box side.

(2)Measure the voltage between headlamp relay (HI) connector terminal No. 2/4 and the body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 5.

Go to Step 7.

STEP 5. Connector check: C-312 ETACS-ECU connector

Q. Is the check result normal?

Go to Step 6.

Repair the defective connector.

STEP 6. Wiring harness check between the A-20X headlamp relay (HI) connector terminal No. 1 and the C-312 ETACS-ECU connector terminal No. 13

Check the output lines for open circuit.

Q. Is the check result normal?

Go to Step 8.

Repair the wiring harness.

STEP 7. Wiring harness check between the A-20X headlamp relay (HI) connector terminal No. 4 and the fusible link (34)

Check the power supply line for open circuit.

Q. Is the check result normal?

Go to Step 8.

Repair the wiring harness.

STEP 8. Retest the system

Check that the headlamps (high-beam) 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 ETACS-ECU.