DTC P1C08: 12V Battery Relay Performance Or Stuck Off: Wiring Diagram

WARNING: This page is about a different car, the 2015 Subaru XV Crosstrek. However, it is still accessible from the selected car via links, so may be relevant.

Power Supply Circuit < Ref. to WIRING DIAGRAM , Power Supply Circuit.>

Fig 1: 12V Battery Relay Performance/Stuck Off - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DTC PROCEDURE

Step	Check	Yes	No
1 CHECK CONNECTOR. Check the connector (B598) of 12V engine restart battery sensor.	Is there looseness or poor contact of connector?	Repair the connector.	Go to step 2 .
2 CHECK FUSE. Check the slow blow fuse of the 12 volt auxiliary battery and 12 volt engine restart battery.	Is the condition normal?	Go to step 3 .	Replace the fuse. When the replaced fuse is blown immediately, repair ground short circuit of harness between 12 volt engine restart battery and the 12 volt battery relay and the harness between 12 volt auxiliary battery and the 12V battery relay.
3 CHECK RELAY. Using the Subaru Select Monitor, perform «12V Battery Relay Operation» of System Operation Check Mode for the hybrid powertrain control system. < Ref. to HYBRID POWERTRAIN CONTROL SYSTEM , OPERATION, System Operation Check Mode.>	Does the relay operate?	Even if DTC is detected, 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.	Go to step 4 .
4 CHECK RELAY. Check the 12V battery relay. < Ref. to 12V BATTERY RELAY .>	Is the condition normal?	Go to step 5 .	Replace the 12V battery relay.
5 CHECK TERMINALS. Check the 12V battery relay for loose bolts or corrosion.	Is the condition normal?	Go to step 6 .	Repair the terminals.
6 CHECK HARNESS (SHORT TO GROUND). Using a tester, measure the resistance between 12V battery relay connector and each battery. Connector & terminal Positive terminal of 12 volt engine restart battery - 12V battery relay terminal (12 volt engine restart battery side): Positive terminal of 12 volt auxiliary battery - 12V battery relay terminal (12 volt auxiliary battery side):	Is the resistance 1 Ω or less?	Replace the HPCM. < Ref. to HYBRID POWERTRAIN CONTROL MODULE .>	Repair the open circuit in harness between the 12V battery relay connector and each battery.