DTC B2A07: Backup Battery Charge System Performance

Diagnosis start condition:

When ignition switch is ON.

DTC detecting condition:

Backup battery is disconnected for at least 5 seconds when the ignition switch is turned ON. (Detached backup battery connection, etc.)

Trouble symptom:

ACN/SOS function cannot be used when the main battery is disconnected.
RED LED illuminates.

CAUTION:

After the DCM is replaced, registrations of CommCheck and immobilizer system are required. Ref. to ENTERTAINMENT & MONITORING>TELEMATICS SYSTEM>OPERATION>REGISTRATION (COMM CHECK) .
Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to TELEMATICS SYSTEM (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

CHECK DTC .
Read the DTC of [Telematics] using the Subaru Select Monitor. Ref. to TELEMATICS SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

Is DTC B2A07 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.

NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
CHECK THE BACKUP BATTERY .
1. Remove the DCM. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE>REMOVAL>DATA COMMUNICATION MODULE .
2. Remove the backup battery cover.
3. Disconnect the backup battery connector.
4. Measure the backup battery voltage. (Preferably after one hour of charging)
Is the voltage 2.0 V or more?

Yes: Replace the DCM. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE .

No: Replace the backup battery. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE>REMOVAL>BACKUP BATTERY . If the fault is not fixed, replace the DCM. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE .