Electrical problems out of nowhere! Really, really weird. Car won't turn off properly!

[Stu]

Walked outside to my car to drive somewhere, only to find that the headlights were on.

"No big deal," I thought, "I must have accidentally hit the switch last night when I was checking my oil."

I plop into the driver's seat to see the following:

No key in the ignition:

- DSC light on
- Temperature gauge in the red
- Seatbelt light on
- Red bake light on
- Cruise control light on
- Fuel gauge being measured
- Error light blinking on headlights, headlights in the auto position, perfectly sunny out, headlights on

http://i.imgur.com/uHE3I0Al.gif (http://imgur.com/uHE3I0A)

I turn the car on, starts up just fine, errors all go away. Turn the car off, take the key out of the ignition, all the lights tun on. The fact that the car turned over means that this just happened very recently, as in the past hour or so.

I unplugged my battery and am going to reset the ECU to see if it fixes it.

I looked in my engine compartment, no condensation, no water, nothing wrong around the ECU.

This came out of nowhere. The car has been driving beautifully, no electrical problems anywhere. Has this happened to anyone?? What can I do if it keeps coming back?

[kayger12]

How old is the battery?

[Stu]

Not sure. Last time I had it checked, it seemed to be good, which was about 3 weeks ago.

[kayger12]

Check the voltage it's putting out via the hidden obc function.

Crazy electrical gremlins in the E46 usually means the battery is on the way out.

[Stu]

Update. Resetting ECU seemed to fix it.

You might be right, it could be time for a new battery or voltage regulator. I'll get it tested and take a look.

I need to go head to the VW dealer to get a T-clamp for the neg. battery terminal - I freakin broke mine, and BMW doesn't sell them individually!

[az3579]

Replace battery. Call it a day.