DTC B2A0F: Backup Battery Degradation

Diagnosis start condition:

When ignition switch is ON.

DTC detecting condition:

The voltage does not reach 4.1 V after the backup battery is charged for 7 hours in total (not continuously).

Trouble symptom:

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 B2A0F 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 .
Check the backup battery unit. Ref. to ENTERTAINMENT & MONITORING>DATA COMMUNICATION MODULE>INSPECTION>BACKUP BATTERY .

Is the check result OK?

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 .