A loose or worn gas cap could be cause the Check Engine Light to illuminate.
2008 Cadillac STS-V Problem Reports
RepairPal Verified 2008 Cadillac STS-V Problem Reports
The rear axle pinion seal may leak causing fluid loss and possible internal rear end damage. Replacing the faulty seal will commonly correct this concern.
The front turn signal and and daytime running light bulbs are prone to premature failure. Our technicians tell us that these bulbs can be very difficult to replace.