Hey all,

I recently bought an '09 JCW Coupe with 40k on the clock and I'm having electrical gremlins... The car's battery dies randomly. I can drive the car all afternoon with it starting perfectly fine. Then, if I come back to it a couple of hours later, it may be totally dead. The battery is new and tests fine for holding a charge.

I have also noticed that both power windows were rolling themselves slowly down when parked or opened/closed (window regulators?), now only the passenger side does this. So essentially I come back to a dead car with the passenger window cracked open.

Now the worst part is that every time the Mini dies, it throws a code that makes the engine fire wrong, leading to a sputtering, lumpy start and inability to idle. After a few moments the car coughs to death.

The first time this happened I had the car towed out to a shop where I paid to have it fixed. My understanding is that they cleared the OBDII codes and it ran like normal again.
About a week later I drove it all day, then put it in the garage for a few hours. Upon trying to start it again the passenger window was down, battery was dead, and after charging it the car couldn't maintain idle and sputtered to death.

I don't have a scanner at home, and I really want to avoid having it towed again. Has anybody on here experienced something similar? I searched high and low for answers to this... Thanks.

 

Given that the windows appear to be part of this issue I would suggest that you try to re-set the windows up and down 'home' positions by holding the switches up for 10 seconds then down for 10 seconds.

Also, you may want to try to pull the fuse that controls the windows and see if that helps if the above does not.

If you can isolate the issue to them causing the battery drain and go from there that would be best.

Good luck.

 

I tried the window reset and that problem appears gone. Thanks for your help.

My big problem now is getting the car to stay running.

If it's only an OBDII problem like my mechanic said is there a way to clear the code without a scanner? I tried disconnecting the battery, etc. Didn't expect that to do anything but thought it was worth a try.

 

You can buy a cheap odb2 reader for about $30....
Some folks report A $5 odb2 Bluetooth plug and a phone app can do it...
But just clearing a code will not fix problem....its is just the info the computer is spitting out that shows there was a problem....

 

I know these cars are sensitive to low battery conditions and yours has had a work out. If you go to any big auto parts store they'll test both the battery and may be able to re-set the codes for you. If the battery is in poor shape it may be worth a new one and see how it all works out.

If you have a '09 on the original battery it's likely due anyway and you won't be out much for a part that is well within the end of it's useful life.

 

He said its a new battery in his first post!

 

Missed that. Given what is has been through maybe re-testing it would not be a bad idea anyway? It's free at the big-box auto stores so I would get that done and have them try the codes too.

 

I can take out the battery and have it re-tested at an auto parts store, but I'm pretty confident that the battery isn't the issue. I think something, most likely the windows, has been drawing power from the battery while parked.

Both times the battery has died it refuses to run at all afterwards. After the ignition turns over the engine coughs and dies. The first time my mechanic simply cleared a code that was triggering the engine to fire incorrectly and it worked normally again. He said this was the only issue related to the running of the car. The car ran flawlessly until it randomly died again in my garage... Now it's spent more time broken than driveable in my possession.

Has nobody else had a similar experience with the idling/running problem?

 

The way it was described to me was basically that there is no mechanical issue. After the code was cleared it ran perfectly again. I don't understand why the car would do this simply from a dead battery, either.

 

19 years ago I was driving down from Northern California and in the middle of the I5 freeway my engine couldn't maintain idle and sputtered to death just like you describe, also the headlights were really dim just before it died. It turns out that my battery exploded spilling battery juices everywhere under the hood, my alternator died and my cars electrical system was drawing all its electricity from the battery. Have you had your alternator checked out? It could be charging and then not charging at random.

Hope this helps.