So last month a couple times when it was real cold i would have to use a jump pack to start the car.

2 weeks ago i put a new battery. Today its pretty cold and wouldnt start again. i was in a rush so i used the jump pack and started it up and drove fine. Couple minutes later i realized the CEL was on. Got home left it running, used my cheap scanner and got that code.

Tried to clear it but wouldnt clear. I shut it off and started it a couple times and started fine but the CEL stayed and still wouldnt clear when i tried to clear it when it was running or just key on.

Car has 186k and i have a wrx that i need to finish an engine swap on so the battery i got was a reman interstate since i wont be driving this car much once i finish the wrx engine swap.

 

Looks like you need another battery to me and register it

 

And the code you got was?

A cheapy code reader cannot read or clear BMW specific codes.

 

Ya im thinking another battery as well. Its got a warranty so ill bring it back n swap it out.

Ive got codes with it before on this car. This u0100 code was something like failure to connect to pcm or something along those lines, i forget the exact wording. Last time i hooked my snap on scanner to this car i wouldnt pull codes. It IDed the car and a couple other things but wouldnt pull the codes.

Last night it started on its own and the CEL wasnt on. Today got over a foot of snow and it wouldnt start again.

 

If your battery and / or charging feedback loop has issues, you're going to get potentially unrelated codes.