Received my B200 from a UK shop on ebay. Hooked it up to the OBD socket (in footwell under flip down cover above pedals) and it showed Table 10 code 05 Firing circuit, left hand front seat airbag (passenger side). Did a reset a couple of times with ignition on but light stayed on initially, however on switching off and starting car the air bag light now goes out as normal.
Light originally came on months ago when passenger seat was moved. Just fiddled with the 2 connectors under seat but if it comes on again I will solder them up instead of paying BMW £300+ to fix a new harness.
Another happy with B200 tool here thanks rgn !
