Take a visit over to the M5board.com and look through the FAQ's. You will need a Peake reader to run the codes and post what codes were pulled. I would first suggest to reset the codes and see what comes back.
We, over at M5board.com are very friendly and helpful to new "Beast" owners. Just use the search function first and don't start an oil thread.
2002 M5 Bluewater Metallic~Black & Silverstone leather~All options~MKIV NAV~VMR VB3 Square set-up~3M tint~BT~Intravee II~Ice V5 AE~DINAN Front/Rear Strut Braces~PowerChip Alpha-N tune~Smoked taillights~Ultimate pedals~BSW Stage 1 Upgrade w/Subwoofer~e60 SSK~ZHP Shift Knob~CF Kidneys~CNS Racing exhaust~LED lighting~Hella Euroclear Headlights~Angeleye DRL's~HID Foglights~Dinan Stage 2 Suspension~CNS Racing Clutch~Sink drains~ExoticsTuning CF diffuser/fog light covers~SuperSprint Headers