Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc b2a0f backup battery degradation

Subaru Legacy BN/BS (2015-2019) Service Manual / Telematics system (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc b2a0f backup battery degradation

DIAGNOSIS START CONDITION:

When ignition switch is ON.

DTC DETECTING CONDITION:

• Backup battery voltage of charger is low.

• Charging attempt of 2 V or more fails after the backup battery has been charged for 1 hour continuously.

• Full charging is not achieved after the backup battery is charged for 7 hours in total (not continuously).

TROUBLE SYMPTOM:

RED LED illuminates.

CAUTION:

CommCheck is required after replacing the DCM. Telematics System > OPERATION

STEP	CHECK	YES	NO
1.CHECK DTC. Read the DTC. Diagnostic Code(s) Display	Is DTC B2A0F displayed- (Current malfunction)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2A0F BACKUP BATTERY DEGRADATION	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. In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2.CHECK THE BACKUP BATTERY. Check the backup battery unit. Data Communication Module	Is the backup battery OK-	Replace the DCM. Data Communication Module	Replace the backup battery. Data Communication Module

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Inspection
1. DIODECAUTION:There is the possibility of damaging the diodes if a mega-tester (used to measure high voltages) or a similar measuring instrument is used. Never use a mega tester or equivalent for this test.1. Check for continuity between the diode lead and terminal E or B. If continuity is not as ...