I would definately take it a couple other places before doing anything to it. Being a girl, otherwise known as a complete moron to "car guys", I know they can be assholes. In my opinion, I don't care where you go but if they're good enough with cars, they won't need a book. They should be able to check your car for a ton of things that might be making the light come on rather than following what the "book leads to". I could be completely wrong though, they might know exactly what they're doing, I just know that 2nd, 3rd, and 4th opinions are always nice.