Have an 2005 Audi TT 1.8L very good condition but and the 2 diagnostic units I have will not connect. they light up when plugged in to car but nothing , link error ,no codes as a guy I used to work with plugged his lap top in no problem, so do I buy a similar system for my lap top, but I don't think I should do. A problem I have is the pass air bag light goes off on centre console but not on speedo , is that an MOT fail, so 2 things now what.