Short-to-ground error and charge deficiencies in BMW – how to fix?

BMW driver question

I bought a used BMW 3 with two faults: an auxiliary water pump generates a short-to-ground fault and a shortage of boost. From what the seller told me, the “oil mist“ can damage the alternator and the main belt of the belt system. What could be the cause of such faults?

The problem affected a BMW 320d E90, but it can also happen in other models.

BM Cars service response

1. A short to ground error in the auxiliary water pump requires a check of the electrical system before deciding to replace the pump. The auxiliary water pump on your model is only relevant in terms of heating efficiency at standstill in very low ambient temperatures. The basic functions of heating the cabin are carried out using the main water pump driven by a multi-ribbed belt.
2. There should be no oil (“oil mist”) in the supercharging system. Describing exactly, the oil should not be there if the crankcase vent system (the air cleaner) is in working order and the turbo does not show excessive play.

You are welcome to use the services of BM Cars.

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