The Steering Responsive Headlight Does Not Operate

Detecting condition :

Malfunction of VDC control module, LAN communication circuit, actuator power supply circuit, reverse signal circuit, switch circuit, actuator, auto headlight beam leveler control module power supply circuit, auto headlight beam leveler control module

Wiring diagram :

Headlight beam leveler system Ref. to WIRING SYSTEM>HEADLIGHT BEAM LEVELER SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Before performing diagnosis, check the fuse in this circuit . Ref. to LIGHTING SYSTEM>RELAY AND FUSE>INSPECTION .
Initialization is required after replacing the auto headlight beam leveler control module . Ref. to LIGHTING SYSTEM>AUTO HEADLIGHT BEAM LEVELER SYSTEM>PROCEDURE .

CHECK DTC .
1. Turn the ignition switch to ON.
2. Start the engine.
3. Using the Subaru Select Monitor, perform the clear memory of [Headlight/Foglight]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
4. Read the DTC of [Headlight/Foglight] using the Subaru Select Monitor. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Are any DTCs displayed? (Current code)

Yes: Perform the diagnosis for the displayed DTCs. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

No: Go to 2.
CHECK DTC .
Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Are any DTCs displayed? (Current code)

Yes: Perform the diagnosis for the displayed DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

No: Go to 3.
CHECK DATA MONITOR .
Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Headlight/Foglight]. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DATA MONITOR .
- ECU ACC
Does [Data Monitor] indicate the standard value?

Yes: Go to 5.

No: Go to 4.
CHECK HARNESS BETWEEN POWER SUPPLY - AUTO HEADLIGHT BEAM LEVELER CONTROL MODULE .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the auto headlight beam leveler control module.
3. Turn the ignition switch to ON.
4. Measure the voltage between the auto headlight beam leveler control module connector and chassis ground.
  Connector & terminal
  
  (B78) No. 1 (+) - Chassis ground (-):
  
  (B78) No. 3 (+) - Chassis ground (-):
Is the voltage 8 - 16 V?

Yes: Replace the auto headlight beam leveler control module. Ref. to LIGHTING SYSTEM>AUTO HEADLIGHT BEAM LEVELER CONTROL MODULE .

No: Repair or replace the harness.
CHECK ACTIVE TEST FOR SWIVEL ACTUATOR .
1. Turn the ignition switch to OFF.
2. Connect all the disconnected connectors.
3. Start the engine.
4. Using the Subaru Select Monitor, check the following items in the [Active Test] of [Headlight/Foglight]. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>ACTIVE TEST .
  - Right Steering Responsive Headlight
  - Left Steering Responsive Headlight
If the actuator current position values are approximately the same as the input value of the actuator control position, go to A.

If the actuator current position value is not the same on one side only as the input value of the actuator control position, go to B.

If the actuator current position values are not the same on both sides as the input value of the actuator control position, go to C.
1. Go to 8.
2. Replace the headlight assembly on the side where the same value is not achieved. Ref. to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY .
3. Go to 6.
CHECK DATA MONITOR .
Using the Subaru Select Monitor, check the following items in the [Data Monitor] of [Headlight/Foglight]. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DATA MONITOR .
- Left Steering Responsive Headlight Power Supply Failure
- Right Steering Responsive Headlight Power Supply Failure
Is [Abnormal] displayed?

Yes: Go to 7.

No: Go to 8.
CHECK SWIVEL ACTUATOR POWER SUPPLY VOLTAGE .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the headlight assembly RH.
3. Disconnect the connector from the headlight assembly LH.
4. Turn the ignition switch to ON.
5. Using a tester, measure the voltage between headlight assembly connector and chassis ground.
  Connector & terminal
  
  (B121) No. 10 (+) - Chassis ground (-):
  
  (B122) No. 10 (+) - Chassis ground (-):
Is the voltage 8 - 16 V?

Yes: Replace the headlight assembly. Ref. to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY .

No: Repair or replace the open circuit of battery or harness.
DRIVING CHECK .
Perform the road test to make sure there is no yawing.

Is it yawing?

Yes: Check the vehicle alignment.

No: The circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.