OK changed the IAT sensor out last night. Not thinking I turned the key to the on position while the sensor was out to see what time it was. Put everything back together changed my oil. Started the truck, check engine light comes on. Checked all my connections. Found nothing loose. Then realized what I had done (turning key on while unplugged). How do I check for error code and the interpretation of the code if I can even get it. How do you clear the check engine light? Truck runs fine. Trying to find the source of my fuel milage loss. There was a slight resistance difference between the two IAT sensors, but since the new one was only $18.00 I went ahead and changed it out

 

AutoZone can read and reset codes. They didn't charge me anything to do mine on Monday.

 

You can also clear inactive codes by turning the key to the start postition, then off 5 times. If the code is not active, the check engine light should go off on the 6th try.