A Loose or worn gas cap may cause Check Engine Light to illuminate.Google+
Car Problem Reports
Saturn Sky Red Line Check Engine Light Due to Gas Cap Issue
Saturn Sky Red Line Problem
Average Mileage: 47,250 mi (19,500 mi - 75,000 mi)
Visitor, 2007 Saturn Sky Red Line, 75,000 mi
Same issue. Just got a new cap, but warning light did not go off immediately when replaced.