Bests & Worsts Reviews from Amazon

Has worked well when the check engine light comes on. I had an issue with my coolant thermostat and was able to diagnose it before visiting the mechanic through the web with the code I got and the symptoms I had. I wanted to see if the new mechanic place was going to be honest (I just moved to a new state), so I didn't say anything about it except the check engine light went on. The mechanic told me that was the issue and nothing else, I knew I found a good mechanic.