DTC B1A01: Front Relay Control Module Battery (Control) Power Supply

DTC detecting condition: 

When the ignition is ON or during CAN communication, battery voltage exceeded the range of 9 - 16 V for 40 seconds or more.

Trouble symptom: 

Headlight does not illuminate and the wiper does not operate.

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. 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 B1A01 displayed? (Current code)

   Yes  : Go to  2.

   No  : Go to  5.

2. CHECK DTC  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connectors (B68, B69) from Front relay control module.
   3. Connect the disconnected connectors.
   4. Turn the ignition switch to ON.
   5. Wait approx. 1 minute.
   6. 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 B1A01 displayed? (Current code)

   Yes  : Go to  3.

   No  : Go to  5.

3. CHECK FUSE  .
   1. Turn the ignition switch to OFF.
   2. Check the fuse. Ref. to WIRING SYSTEM>HEADLIGHT SYSTEM>WIRING DIAGRAM

   Is the check result OK?

   Yes  : Go to  4.

   No  : Replace the defective fuse.

4. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Disconnect the connector (B68) from Front relay control module.
   2. Using a tester, measure the voltage between Front relay control module connector and chassis ground.

      Connector & terminal 

      (B68) No. 5 (+) - Chassis ground (-):

   Is the voltage 8.5 - 16.5 V?

   Yes  : Replace Front relay control module. Ref. to BODY CONTROL/COMMUNICATION SYSTEM>FRONT RELAY CONTROL MODULE

   No  : Repair the harness between Front relay control module and fuse.

5. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector (B68) 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  : 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.