[adannenberger]

HELP! I used my aux battery to jump another car. Engine light came on got it scanned p305f I believe. Aux battery has been replaced, main battery was tested ok, alternator was test ok, starter was tested ok, all are good. When I start my car now it is a 50/50 shot if it will start up without a problem. Sometimes it does other times there is a long delay and then you can hear it crank several times and then start. I have scanned it again and it said dual battery control module. Often the battery saver mode will become active or I will get a service engine soon or service power steering warning. Anyone have any recommendations on what I need to replace or look at. Its driving me crazy 2016 malibu limited

 

[DrivenDaily]

Please share more info about your car.

Never, ever, ever use the Aux battery to jump another car. It is there to supply juice to the radio, HVAC, and other items when your engine is off. The main battery under the hood always starts your engine, so that is the one you should use to jump another car.

You probably fried the DBCM and who knows, maybe some wiring or plugs as well.

 

[repairman54]

Yep you blew up the battery module.