Found this on another forum, don't know if it helps? Surprised they could not find what was wrong because I can tell you exactly what is wrong The older E46 saloons had a fault where either the passenger presence airbag mat would fail randomly or the airbag loom under the seat would break/corrode at the connections resulting in the airbag light being turned on. I'm betting it's the mat though because of the loom had failed the light would come on and stay on until manually reset. Airbag mats are around £60 give or take and when I had my old saloon in at a Indy (Autotechnik, Fareham)they quoted me £96 for a replacement mat inc fitting.