DTC B1012: Battery Backup Power Supply

DTC detecting condition:

Voltage failure caused by poor contact of battery power supply backup circuits

Trouble symptom:

Illuminations for the keyless entry, map light, luggage light, trunk light, room light, and ignition switch do not turn on.

NOTE: When [DTC B1011 BATTERY CONTROL POWER SUPPLY] is output at the same time, all function of body integrated unit may not operate.

Wiring diagram:

Immobilizer system Ref. to WIRING SYSTEM (IMPREZA MODEL)>IMMOBILIZER SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>IMMOBILIZER SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>IMMOBILIZER SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to BODY CONTROL (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

CHECK DTC .
1. Turn the ignition switch to ON.
2. Read the DTC of [Body Control] using the Subaru Select Monitor. Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1012 displayed? (Current malfunction)

Yes: Go to 2.

No: Go to 5.
CHECK DTC .
1. Turn the ignition switch to OFF.
2. Disconnect and then connect the body integrated unit connector.
3. Wait approx. 2 minutes.
4. Turn the ignition switch to ON.
5. Read the DTC of [Body Control] using the Subaru Select Monitor. Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1012 displayed? (Current malfunction)

Yes: Go to 3.

No: Go to 5.
CHECK FUSE .
1. Turn the ignition switch to OFF.
2. Check the fuse.
Is the check result OK?

Yes: Go to 4.

No: Replace the defective fuse.
CHECK HARNESS .
1. Disconnect the body integrated unit connector.
2. Using the tester, measure the voltage between terminals.
  Connector and terminal
  
  (B281) No. 7 (+) - Chassis ground (-):
Is the voltage 8.5 - 16.5 V?

Yes: Replace the body integrated unit. Ref. to SECURITY AND LOCKS>BODY INTEGRATED UNIT .

No: Repair the harness between body integrated unit and fuse.
CHECK CONNECTOR .
1. Turn the ignition switch to OFF.
2. Disconnect the body integrated unit connector.
Is there poor contact of 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.