[redz06]

I have a 2011 335i Sedan which was my European Delivery car. In 28 months it accumulated 37000 miles, mostly in tollway driving in Houston. A lot of these miles were accumulated an indicated 80 mph. After 28 months the battery failed, leaving me stranded at our local pharmacy. Jump-starting the car using the BMW recommended terminal points was not successful (this may give some of you pause for thought). Finally the car started when jumped simultaneously from two vehicles, one providing power to the jumper points under the hood and another providing power to the battery terminals.

I drove the car to my local BMW dealer straight-away, and left the car for diagnostics and service. Realistically, I expected the battery would be replaced under warranty before the end of the day.

This was not to be. Before the end of the day my service advisor called me stating that the battery had failed and that BMW expected that the failure was caused by the aftermarket audio amplifier that was installed on the car. When I asked what was the reason for BMW's expectations, I was told that the amplifier was the only part that BMW had not installed on the car, so the amplifier was clearly the cause of the problem.

At this point, I informed my service writer that the aftermarket amplifier (a JL 600/6) had been installed and operating flawlessly for over 18 months, including two visits to the BMW dealer, with no previous complaints from BMW. I also informed the BMW dealer that I had installed the aftermarket amplifier myself and that the installation was perfect.

The service writer said that it would be necessary for BMW to keep my car for testing until the next Monday, such that BMW could prove that my amplifier was responsible for the problem. The service writer stated that for service work to go forward, it would be necessary for me to agree that I would pay $550.00 to replace the battery, should BMW show that my amplifier is responsible for the damage to the battery.

I agreed, but I did insist that BMW provide me with a loaner car while they went through multiple days of checks on my vehicle. They promised that I would have my car back by the next Monday (3 days of inconvenience to me).

BMW service is surely slow, as 3 days was not enough to tend to a defective battery, neither was 4 days, 5 days, or 6 days. Finally after more than 7 days my battery was replaced under warranty. This was inconvenient to me as I had signed a statement that I would not take the loaner car on the tollway which is necessary for my daily commute. It was also stupid for BMW as I was using their loaner car, a new BMW 328 sedan during the week that they wasted with my car in service. I think you can figure out that this story does not build confidence in BMW service policies.

In conclusion, I have to warn folks that are installing high quality audio equipment in their BMWs that BMW dealers may find that installation of such equipment is the cause for any problems that may occur with the cars. I guess the low quality equipment installed at the factory is OK.

[cdgatti]

Not surprising. Our cars have stickers all over them warning that aftermarket parts will void warranties. In your case that amp is a very efficient, relatively low power drawing unit, but they have to protect themselves from people doing outrageous things then blaming bmw and wanting warranty coverage.

[ctuna]

You are lucky you got a new one.
Most don't even if they have no mods.
They say its driver profile .

[Jgcdude1]

There's a recall for batteries from a particular supplier to BMW. If your vehicle has that specific battery lot code, then it gets replaced.

Just took mine 2011 e93 and the battery was replaced.

Hope this helps.