A Loose or worn gas cap may cause Check Engine Light to illuminate.
Car Problem Reports
Cadillac Seville SLS Check Engine Light Due to Gas Cap Issue
Cadillac Seville SLS Problem
Average Mileage: 105,500 mi (68,000 mi - 143,000 mi)
Visitor, 2001 Cadillac Seville SLS, 68,000 mi
Check Engine light came on, fuel leak detected, check gas cap came on around a week later, changed and services engine soon turned off.