DTC B1A0A: Head Lamp Hi RH Circuit Current High

DTC detecting condition: 

When over-current is detected while the headlight High is output.

Trouble symptom: 

Right side of the headlight High does not illuminate.

Wiring diagram: 

Headlight system Ref. to WIRING SYSTEM>HEADLIGHT SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Turn the lighting II SW to ON.
   3. Set the dimmer Hi SW to ON.
   4. Read the DTC of [Front Relay Control Module] using the Subaru Select Monitor. Ref. to FRONT RELAY CONTROL MODULE (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) 

   Is DTC B1A0A displayed? (Current code)

   Yes  : Go to  2.

   No  : Even if DTC is displayed, 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. 

2. CHECK FRONT COMBINATION LIGHT RH  .
   1. Using the Subaru Select Monitor, check the following items of [Active Test] of [Front Relay Control Module]. Ref. to FRONT RELAY CONTROL MODULE (DIAGNOSTICS)>ACTIVE TEST 
      • Lighting High RH Output
   2. Check that the right side of headlight High illuminates.

   Is the check result OK?

   Yes  : Even if DTC is displayed, 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. 

   No  : Go to  3.

3. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connectors (B68, B69) from Front relay control module.

   Is there poor contact of Front relay control module connector?

   Yes  : Repair or replace the poor contact of connector.

   No  : Go to  4.

4. CHECK HARNESS (GROUND SHORT CIRCUIT)  .
   1. Disconnect the front combination light RH connector.
   2. Using a tester, measure the resistance between Front Relay Control Module connector and chassis ground.

      Connector & terminal 

      (B69) No. 2 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  5.

   No  : Repair or replace the short circuit of the harness.

5. CHECK FRONT COMBINATION LIGHT RH  .
   1. Apply a voltage equivalent to the battery voltage between the front combination light RH connector terminals.

      Connector & terminal 

      (B121) No. 1 (+) - (B121) No. 2 (-):

      (B121) No. 3 (+) - (B121) No. 2 (-):

   2. Check that the right side of headlight High illuminates.
      NOTE:

      Light distribution of the Lo/Hi beams are switched from a single light instrument, so confirm that the current light emission is Hi beam. 

   Is the check result OK?

   Yes  : Replace Front Relay Control Module. Ref. to BODY CONTROL/COMMUNICATION SYSTEM>FRONT RELAY CONTROL MODULE

   No  : Replace the front combination light RH. Ref. to LIGHTING SYSTEM>HEADLIGHT ASSEMBLY