A Loose or worn gas cap may cause Check Engine Light to illuminate.Google+
Car Problem Reports
Saturn Aura Check Engine Light Due to Gas Cap Issue
Saturn Aura Problem
Average Mileage: 48,033 mi (38,000 mi - 53,100 mi)
Visitor, 2007 Saturn Aura, 53,100 mi
Gas cap seems to be loose. Won't fully tighten like I'm used to on other cars. Last time the check engine light came on I took it to a dealer and they said the code was a vapor leak. They reset the code, but now the lights on again. Probably time for a new gas cap.