2 months ago now my 07 E60 530i stopped running. Wouldn't start, even after giving her a jump. She'd just make this low humming sound when I tried. Asked the dealer I got her from and he was convinced it was her starter causing problems. I unfortunately forget his reasoning but I got a new starter and replaced it. And managed to get the car to turn over after sitting hooked up to another car for like 45 mins. She then was able to go from Maryland to Pa (about a 45m-1h drive) with the only complaint from the driver being that she was "Slow on the gas". The next day I get behind the wheel to feel what he was talking about and I find that if I had the pedal to the floor she wasn't even reaching 5mph, if I sat there with the pedal on the floor she would eventually ease up to like 10mph. Parked her, turned her off and went back inside to do some research and I come back out to a car that won't start again. I contact the dealer and he says something is likely draining the battery. So I got a new one, installed it and still she won't start. Still making that hum. I got my hands on an AutoPhix BMW Scanner so I used that to register the new battery. The scanner seems to have alot of potential to help me but alot of the codes I'm looking for can only be scanned if the car is turned on. So I'm in the dark. This is my first car and I am desperately trying to make her work. I've often used these forums as a guide for help but never actually posted of my own volition. I hope that you guys can help shed some light on the situation, thank you for your help.

 

Yes, you could have a parasitic drain. You need a voltmeter to troubleshoot it.