Hi all, regarding the basic OBD2 code readers you can get from places like Amazon for around £20-40, are these actually any good? On my R56 Cooper I have an airbag and seatbelt light on, and I was wondering if one of these readers would tell me more precisely what the issue is, or if problems like this are beyond their technical abilities? Do I just need to suck it up and take it to a garage? Thanks