Originally Posted by Modmike
Wasn't tightened. Never cleared in 3 months.
There something else wrong. 1st off a loose gas cap comes on as a separate notification (it looks like a little light bulb sitting over the right rear tail light) and not the service engine soon light. Get a BT Scan tool if you plan on servicing the car yourself, or at least want to know for what the SES light is on.