Wife started car after work yesterday and the engine light was on, she took it to advance auto parts and they checked the codes and came up with "EVAP emission system control leak". They told her that's usually the gas cap. Any ideas if this is true or what this code actually means? They cleared the code and it runs fine and light stayed off. I checked the gas cap and it has a build up of dirt or something on the seal so maybe that could have caused it? Don't know. '07 Malibu LS 4cyl 43,000 miles.

 

yes, a loose gas cap, or one that is not sealing right can cause the EVAP small leak code. it is the #1 cause for this code. usually tightening cap or cleaning the seal and putting a small bit of oil on it will solve problem.

 

Thanks for posting this. My son's engine light came on so he took the car to auto zone. Code PO455.
Turned out the gas cap was not tight. Tightened up the cap and took the car out for a ride around the block. Half way around the light went off.
Nice...