How to test if battery is going bad?

[righty491]

Hey everyone, this is my first post and I've been enjoying my car since the day I bought it, but now that I'm out of warranty, I've had my first major problem so any advice would be greatly appreciated.

Thursday - I was cruising on the highway for about 20 min when my gauges went dark, went to 0, and then swept back to the speed I was going and my iDrive went crazy. I didn't have enough time to read the fault, but it was there and went away almost immediately.

Yesterday - I was out of town for a couple days, so my car sat, but when I got back in town I went for a drive and the same thing happened again, but instead of happening just once, it happened multiple times, gauges going crazy, interior lights turning off, etc. and this time my iDrive wouldn't register "clicks" (this did however work again when I parked my car and turned it off and on again).

I plugged in my generic OBD2 scanner and found that it's throwing the code P15FE.

After doing some research, this could be a number of problems, so I just ordered this scanner in hopes that I can figure out what is wrong.

I plan on testing the battery CCAs later this evening with a multimeter, but I was hoping someone could shine some light on this situation. I'm really stressing out over this and I don't want to have to go to the dealer, but what else could it be?

Thank you in advanced!

Update: the cable I ordered didn't end up working with BMWWhat and my phone, but I was able to get my generic Bluetooth ODB2 adapter to work for the diagnostics (I will be returning the BMWWhat cable). I ended up clearing the codes and unplugging the battery for an hour and everything seemed all well and good for a little over a day, but just last night my car ended up throwing a TPMS fault and I just scheduled an appointment with the dealer for next Monday.

I've done some searching, and I'm really hoping this is just the battery, but how do I test it to make sure that's the problem? I didn't notice any crazy drop in voltage when starting the car, but is there any specific codes I should be watching out for?

I also posted this in the "electronics" section, so I hope I'm not breaking any rules by posting the same thing in multiple sections, but the more I think of it I probably should have posted my original question here...

[MightyMouseTech]

Does not sound like a battery if strange things are happening 20 min into a drive.

What years does the battery cable recall cover?

[righty491]

I just did some digging and found that my car might be one of them...

http://www.1addicts.com/forums/showthread.php?t=804927

I'll call the dealer tomorrow to see if this is something that was fixed before I bought the car.

[tracer bullet]

FWIW, once it's running you should be on alternator power, batteries tend to relate more to starting the car. That cable might be more the right direction to go?