It is imperative to have the correct voltage regulator installed on your car. Specifically original BMW part.
FUN FACT: Bosch is the Original Equipment Manufacturer, I've bought complete and new Bosch alternator for my engine. Voila, GENERATOR FEHLERTYPE... says INPA. I am not even able to run the INPA generator diagnostic process.
BMW never released their communication protocol between the alternator and DME. Circa 150 EUR, here you go BMW, thank you.
OEM PART CODE: 12 31 7 561 939 (180A)
Not having voltage regulator straight from BMW can result in some miscommunication between your generator and DME, you dont want that. When DME request for certain voltage, it should get the exact amount, not more or less.
Also if youre always getting error like generator is overheated when its obviously not? What could be the culprit? 🙂