I recommend finding the error in a code reader and if its really the sensor you're talking about, replace it and then decide whether to take it to the dealer or not.
If they found out that the ECU bay has been tampered with and its the main cause of your problem, then I'm sure that they will not fix your car on warranty.
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F10 550i M-sport: Space Grey/Oyster Black
E39 M5 : Carbon Black/Caramel
E39 520i : Titanium Silver/Beige (Sold)
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