Step 1. ECU check on the SWS monitor

Check that the power supply and earth lines to the column switch (column-ECU) and the front-ECU and the SWS communication lines are normal.

• Ignition switch: OFF

ECUS TO BE CHECKED

• COLUMN ECU

• FRONT ECU

OK: "OK" are displayed for all the items

Q: Are the check result normal?

"OK" are displayed for all the items:  Go to Step 2.
"NG" is displayed on the "COLUMN ECU" menu.:  Refer to Inspection Procedure A-2 "Communication with the column switch (column-ECU) is not possible" .
"NG" is displayed on the "FRONT ECU" menu.:  Refer to Inspection Procedure A-4 "Communication with the front-ECU is not possible" .

Step 2. Function diagnosis by using the SWS monitor

Check the SWS communication signal, which are related to the low-beam headlamps.

<Selected item> LIGHTING - HEADLAMP LO

• Ignition switch: ON

• Lighting switch: HEAD

Item No.	Item name	Normal conditions
Item 00	HEADLAMP SW	ON
Item 03	PASSING SW	OFF
Item 30	IG SW(IG1)	ON
Item 35	HD AUTO-CUT	OFF

OK: Normal conditions displayed for all the items

Q: Are the check result normal?

Normal conditions are displayed for all the items.:  Go to Step 3.
Normal condition is not displayed for item No.00 or No.03:  Refer to inspection procedure P-5 "The column switch (lighting and turn-signal lamp switch) signal is not received" .
Normal condition is not displayed for item No.30.:  Refer to inspection procedure P-2 "The ignition switch (IG1) signal is not received" .
Normal condition is not displayed for item No.35.:  Refer to Inspection Procedure K-6 "The headlamp automatic shutdown function does not work normally" .

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: Are the check results 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.