Ders

Is it possible that the auxiliary battery is what is throwing the code? Your main battery is in the trunk (Assuming this is the one you replaced) but there is also a tiny battery up front. Directly under neath the cabin air filter and washer fluid reservoir. Can find equivalent replacement online for dirt cheap.

My auxiliary battery went bad on my E55 about a year ago. Got a bright red battery error in the middle of my dash. Everything still worked fine but the message only went away once I swapped out that battery. Main battery was fine.

cetialpha5

Oh yeah, it depends if he has an auxiliary battery. He didn't actually mention the year. There's only an aux battery for 2003-2006. The 2007-2009 didn't have one.

Ders

I wasn't aware that they got phased out after the facelift. Good to know. That's where I'd put my money if his primary battery is new. Especially considering he is having no negative impact on his car other than the dash alert.

Marwan Aassar

hello,
so i recently installed a new battery and like 11.4 when the car is off. can it just be a dead cell?? cuz i have a 3 year warranty from Sam’s.

thanks

kajtek1

Testing the battery is pretty tricky and if you check car voltage on its display, it shows 0.5V lower than on battery clamp.
But regardless 11.4 or 11.9V is discharged battery. Charge it with good charger and recheck with load tester.

Marwan Aassar

i took the battery to sam’s and they said it needed recharging. they tried recharging but wouldn’t go above a specific number so they swapped the battery out u set warranty.
made a world of a difference! when i drove it gave me 12.1 now it’s giving me around 14

thank you so much for ur help!

PSDCampervan

My brand new OEM AGM battery draws down after approximately 3-4 days.This YT video demonstrates a few good methods to narrow down where load is occuring including use of an infrared imager technique that I intend to try first.