Recently I had to replace my battery in my 2006 F150. The next day the Engine Check came on. The shop that changed my battery put a code reader on it and reset it. All was okay until today. After 3 stops doing errands the light came back on. What's going on.?

 

What was the code they reset ??? that's what's going to tell us what's going on !!

 

Can you give us more info. Code numbers, engine? I would look to the connections first to see if you have a loose one. The second would be have the alternator tested. Unrelated would be a heater circuit failure in an O2 sensor. Should code that to.

 

FYI, if you have a gas cap, check the rubber gasket under the top of the cap. If its cracked or hardend replace it. You may have to go through one or two tanks of gas before the light goes out.