This book is an easy to use resource for every car owner regardless of make and model. For example, did you know when using a code reader, the reader will not work if one of your fuses is out, (normally the cigar lighter) but the mechanic will say you may need a computer or some other part. Checking the fuses and replacing a few bad ones will normally take care of that. The owners manual wont tell you the fuse related to the diagnostic output. It talks about the options you have in deciding to either perform a repair yourself or employ the help of a mechanic. You will find that most of the items that signal a check engine condition can be replaced by yourself with a little time and patience. Keep it with your owners manual so its their when you need it.