i justhad this today, first started with the check rear and tail, then check brake light...then the dreaded rear sup inact, thee was no change in ride height or ride quality, checked all fuses and they seemed fine ...but msg was still there. however on removing the rear light assembly there was a hole in the metal of the contacts for the bulb, so after a bit of soldering and filing, all lights now working and the suspension message is gone...i guess various electrical glitches can cause this code to be thrown, i also found out that the faulty contacts from the brake light have caused a " check low beam message to come up. so once again thanks guys as these threads have proved invaluable!!!

driving around i seem to see loads of x5's with blown tail/brake lights and i kinda thot its a little niche market, so one could start a side biz fixing these (meaning Me..lol)