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rob's garage

Hi Rob,

I drive a 2009 BMW 535i and it is a brand new car. However within the past month I have began to have many issues with the battery. The main issue is the battery will discharge for no reason. BMW tells me that I must drive the car for at least 10 minutes on the freeway in order for the alternator to charge the battery. The thing is that my driving habits have never changed since day 1 when I got the car and then all of a sudden a month ago the battery died and the car would not start (conveniently was on my way to catch a flight).

The car was towed to BMW dealership. There was no warranty coverage so I had to pay for them to charge the battery. Three weeks later the computer gave me the battery discharge message so I had to buy a charger to charge it again.

The car has a lot of electronics etc but that's no excuse for the problem I am experiencing. I believe it is a pure engineering flaw. BMW refuses to provide help at all because they claim it's not a warranty issue and that the manual states you must drive 10 minutes on the freeway.

I thought you may have heard about other BMW owners that experienced the same problems and whether or not you can offer me any suggestions or solutions to this problem. I bought a trickle charger from BMW as they advised but I really can't be bothered to use this daily. There must be a long term solution but BMW fails to own up to the issue and fix what I believe is a flaw/bug issue.

Regards, Jason

Jason it turns out that indeed there could be an issue with your Bimmer.

I found a Service Bulletin; number SI B 61 08 00, under the heading, General Electrical Systems, dated January 2010.

This bulletin focuses on the testing of the known parasitic draws of the electronic devices found in your high-tech car. While the draw from the numerous gadgets is quite substantial, it shouldn't have killed the battery that quickly.

This bulletin also mentions that there could be an issue with any number of faulty control modules. The BMW design is rife with these electronic control devices and the testing procedure is very complex.

And Jason, a quick blast around a few on-line blogs has revealed that this is a common problem, with other owners receiving the same comments from various dealers. The quest for you will be to find a dealer willing to take the time to apply this service bulletin and the diagnostic procedure contained within it.

Sorry I couldn't be more help but as is the case with these complicated integrated systems, nothing can replace full-blown hands-on diagnostic strategies.

The real cost of car ownership The sticker price is only the starting point. Do you know what you really pay for your vehicle?

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