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 OFF.
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) .

Is DTC of U-code displayed? (Current code)

Yes : Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

No : Go to 3.
CHECK DTC .
Read the DTC of [Brake Control System] using the Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Is any DTC related to the vehicle speed and steering angle sensor displayed? (Current code)

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

No : Go to 4.
CHECK INITIALIZE FUNCTION .
Perform the function check (the initialize function) for the steering responsive headlight. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>GENERAL DESCRIPTION>INSPECTION>BASIC INSPECTION .

Do the left and right headlights operate?

Yes : Go to 6.

No
- Only one side does not operate: Go to 5.
- Both sides do not operate: Go to 6.
CHECK SWIVEL ACTUATOR POWER SUPPLY .
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 [FAIL] displayed?

Yes : Check the battery and fuse. If no fault is found, check the swivel actuator power supply circuit.

No : Go to 9.
CHECK SWIVEL ACTUATOR POWER SUPPLY .
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 [FAIL] displayed?

Yes : Go to 7.

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

Yes : Go to 8.

No : Check the battery and fuse. If no fault is found, check the swivel actuator power supply circuit.
CHECK SRH OPERATION .
1. Turn the ignition switch to OFF.
2. Connect all the disconnected connectors.
3. Drive the vehicle to verify on which side, LH side or RH side, the SRH improper operation occurred.
NOTE: At night, drive a curve of steering wheel angle approximately 45 degrees or more with vehicle speed at 40 km/h (25 MPH) or more, or drive a curve of steering wheel angle approximately 80 degrees or more with vehicle speed at 15 km/h (9 MPH) or more to check the SRH operation.

Is the improper operation occurring on either left or right side only?

Yes : Perform [VSC (VDC) Centering Mode]. Ref. to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM & H/U)>ADJUSTMENT>VDC SENSOR MIDPOINT SETTING MODE .

No : If the fault is not fixed even after the process, Go to 9.
CHECK ACTIVE TEST OF SWIVEL ACTUATOR .
1. Turn the ignition switch to ON.
2. 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
Is the value of actuator current position approximately the same after inputting the actuator control position of 15 degree? (Within 1.2 seconds)

Yes : Go to 11.

No : When the value is not the same on one side only, replace the headlight assembly of the side where the same value is not achieved. Ref. to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY .

When the value is not the same on both sides, Go to 10.
CHECK AUTO HEADLIGHT BEAM LEVELER CONTROL MODULE POWER SUPPLY .
Using the Subaru Select Monitor, check the following items in the [Data monitor] of [Headlight/Foglight]. Ref. to HEADLIGHT/FOGLIGHT (DIAGNOSTICS)>DATA MONITOR .
- Control module voltage
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 : Check the battery and fuse. If no fault is found, check the auto headlight beam leveler Control Module power supply circuit.
DRIVING CHECK .
Perform the road test to make sure there is no yawing.

Is it yawing?

Yes : Check the vehicle alignment. Ref. to FRONT SUSPENSION>WHEEL 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.