Take the car to Autozone and have the codes read. They will do this for free (unless you’re in California, in which case take it to the dealership or an independent mechanic who is not the mechanic you’ve been taking it to, and pay for a diagnostic). Make sure you get the actual codes (it will be a 5-digit alphanumeric code such as P0100), not the clerk’s interpretation of the codes, and post them here.