Hi im new on here, i was gona download free diagnostic software, does anyone know a good one, also how do i hook it up to my car? have just bought a zafira and the engine light keeps coming on and its losing power while the light is on. The guy i bought it from said he was told it was either the airfilter which he replaced, or the crankshaft sensor which he has given me but that is a bigger job. I wanted to see what comes up on diagostics. grateful for any advice cheers maggie.