Q: My check engine light came on...car isn't overheating no change in engine temp gauges..autozone used one of their testing gages sa

There are several possible reasons for a check engine light to come on. Typically, when the check engine light appears, the first step is to pull the diagnostic codes out of the computer with a scan tool, like you did. The codes you get will give a mechanic an idea of where to start with the diagnostic process. A common misconception is that pulling these diagnostic codes will tell you exactly what parts need to be replaced. In reality, the codes are only a starting point for further diagnosis. I’m not saying that the thermostat does not need to be replaced, but a given code could actually have several root causes. Each diagnostic trouble code will have a test associated with it to determine exactly what is causing the code to be set. If this is something you need a hand in diagnosing and/or repairing, contact a certified mechanic, like those available at YourMechanic.com.