I got a 04/90 535i with the m30, the ac compressor in my car I suspect is going bad because when I got the ac working a few months ago (had to throw a belt on it I took it off because it was in the way of and I didn’t care to put it on till the beginning of spring). When I started the car turned the air on everything seemed good. The next day ac compressor locked up for a second and stalled the engine 3 times and it did that 2 days in a row then the ac works. I didn’t mess with the Freon this year and I charged it last year. I also recently picked up a computer and the bmw diagnostic cable and scanned the car for trouble codes and to clear the airbag light on my car and I got a code 40 for the ac compressor. My question is this, if the ac compressor is locking up internally (not the pulley the belt runs on that’s fine with the ac off) is there a way to fix this issue without replacing it completely since it still works? And second question how does the dme know if the ac compressor circuit has a problem if the ac works every single time I turned it on? I’m currently on a 500 mile road trip and I can feel the ac compressor harshly kickin on and off indicating it might be seizing up, I don’t want to drain the Freon system because it’s summer and it’s my only vehicle I got.