Inspection Procedure A-2: None of the high-beam headlamps illuminate.


caution Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.

COMMENTS ON TROUBLE SYMPTOM


If none of the high-beam headlamps illuminate, the headlamp switch input circuit, the headlamp relay (HI) or the ETACS-ECU may be defective.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code.
When the ignition switch is turned to the "LOCK" (OFF) position, check that the ETACS-ECU does not set the diagnosis code.

Q. Is the diagnosis code set?
Refer to diagnosis code chart .
Go to Step 2.

STEP 2. M.U.T.-III data list
Check the input signal from the dimmer switch.

  • Operate the dimmer switch.
Item No.
 Item name
 Normal condition
61
 Headlamp HI output
 ON
OK: Normal condition is displayed.

Q. Is the check result normal?
Go to Step 3.
Refer to inspection procedure 9 "The column switch signal is not received ."

STEP 3. Check the headlamp relay (HI).
Refer to .

Q. Is the check result normal?
Go to Step 4.
Replace the headlamp relay (HI).

STEP 4. Voltage measurement at headlamp relay (HI) connector.
(1)Remove the headlamp relay (HI), and measure at the relay box side.
(2)Measure the voltage between the headlamp relay (HI) connector (power supply terminal) and the body earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 6.
Go to Step 5.

STEP 5. Check of short to power supply, and open circuit in power supply lines between headlamp relay (HI) connector and fusible link.

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 6. Check of open circuit in H/LP HI line between headlamp relay (HI) connector and ETACS-ECU connector.

Q. Is the check result normal?
Go to Step 7.
Repair the connector(s) or wiring harness.

STEP 7. Retest the system.
Check that the high-beam 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 ETACS-ECU (Refer to ).