Thanks for sharing your experience. So a "bad tank" really means that something is bad with the float system. I wonder if some of these aftermarket tanks are made without the magnet in the float? I mean a poor job of reverse engineering (instead of using a specification) would be to measure the tank dimensions and put a float in, but unless you really understood how the system worked, you would not embed a magnet in the float. Maybe that's it. The manufacturer would probably not get enough complaints to understand their tank was faulty since as we can see from the thread, figuring out why we get the message is not easily obvious. Just a theory...

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2006 X5 4.8is
LeMans Blue over black
Style 168 rims
Blackout grills and hood vents
Aux jack