Step 1. MUT-II/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?

YES:  Refer to diagnosis code chart .
NO:  Go to Step 2.

Step 2. Pulse check

Check the input signals below, which are related to the low-beam headlamps.

System switch	Check condition
Ignition switch (IG1)	When turned from ACC to ON
Headlamp switch	When the lighting switch is turned to the HEADLAMP position

OK: The MUT-II/III sounds or the voltmeter needle fluctuates.

Q: Is the check result normal?

All the signals are received normally.:  Go to Step 3.
The ignition switch (IG1) signal is not received.:  Refer to Inspection Procedure P-2 "The ignition switch (IG1) signal is not received ."
The headlamp switch signal is not received.:  Refer to Inspection Procedure P-5 "The column switch (lighting and turn-signal lamp switch) signal is not received ."

Step 3. Connector check: A-11X front-ECU connector

Q: Is the check result normal?

YES:  Go to Step 4.
NO:  Repair the defective connector.

Step 4. Measure the voltage at A-11X front-ECU connector.

1. Remove the front-ECU, and measure at the relay box side.

2. Voltage between A-11X front-ECU connector terminal Nos.8, 9 and body earth
OK: Battery positive voltage

Q: Is the check result normal?

YES:  Go to Step 6.
NO:  Go to Step 5.

Step 5. Check the wiring harness between A-11X front-ECU connector terminal Nos.8, 9 and the battery.

• Check the power supply line for open circuit.

Q: Is the check result normal?

YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Repair the wiring harness.

Step 6. Retest the system.

Check that the low-beam headlamps illuminate normally.

Q: Is the check result normal?

YES:  The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
NO:  Replace the front-ECU.