Intermittent Alternator Charging

Asked by FredSwims May 06, 2018 at 01:20 PM about the 2015 Subaru Outback 3.6R Limited

Question type: Maintenance & Repair

I had to jump start my car three times. I noticed once started the voltage
across the battery is 14 volts but then drops to 12 volts. If I turn on the lights,
the engine speeds up and the voltage goes to 14 volts. When I shut off the
lights the speed drops and the voltage drops to 12 volts. (Increasing the
motor speed alone does not push the alternator up to 14 volts. It appears to
me the alternator or regulator is intermittent. I suspect while the car is
running the voltage across the battery should always be 14 volts indicating
the alternator is charging the battery. Is this correct. What do you think is
wrong?

2 Answers

48,130

Lots of early battery failures in '14-15 Subies. Start there, as nice Interstate choices are at COSTCO under $80.

2 people found this helpful.
90

I know the question was asked a long time ago, but Subaru is having failures with the hardware/software module that controls amp transfer to battery. Can cause battery to under charge or over charge. In my case it burnt out my battery. Both the battery and software had to he replaced. Subaru has a software update which should be installed - why they haven't made it a recall is beyond me

9 people found this helpful.

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