Inspection Procedure 1: The Low-beam Headlamps do not Illuminate Normally.


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


COMMENTS ON TROUBLE SYMPTOM


If the low-beam headlamps do not illuminate, the headlamp switch input circuit, the headlamp relay (LO) 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 headlamp (low-beam) switch.

  • Turn the headlamp (low-beam) switch to the ON position.
Item No.
 Item name
 Normal condition
60
 Headlamp output
 ON
OK: Normal condition is displayed.

Q. Is the check result normal?
Go to Step 3.
Refer to inspection procedure C-1 "The column switch (lighting and wiper switch) signal is not received ."

STEP 3. Connector check: A-22X headlamp relay (LO) connector

Q. Is the check result normal?

Go to Step 4.

Repair the defective connector.

STEP 4. Check the headlamp relay (LO).
Refer to .

Q. Is the check result normal?
Go to Step 5.
Replace the headlamp relay (LO).

STEP 5. Voltage measurement at A-22X headlamp relay (LO) connector.

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

(2)Voltage between A-22X headlamp relay (LO) connector terminal Nos.2, 4 and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 7.

Go to Step 6.

STEP 6. Check the wiring harness between A-22X headlamp relay (LO) connector terminal Nos.2, 4 and the fusible link (23).



  • Check the power supply line from the fusible link (23) 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 7. Connector check: C-218 ETACS-ECU connector


Q. Is the check result normal?

Go to Step 8.

Repair the defective connector.

STEP 8. Check the wiring harness from A-22X headlamp relay (LO) connector terminal No.1 to C-218 ETACS-ECU connector terminal No.17.




note Prior to the wiring harness inspection, check the junction block connector C-211 and repair if necessary.

  • Check the earth wires for open circuit.

Q. Is the check result normal?

Go to Step 9.

Repair the wiring harness.

STEP 9. Retest the system.
Check that the low-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.