Gas Cap Replacement
The purpose of a Gas Cap is twofold: one, it helps prevent dust and other particles from getting into the gas tank, and two, it helps prevent fuel emissions from entering the atmosphere. If your gas cap is faulty, the Check Engine light may come on. Additionally, your vehicle may fail a smog test if the gas cap is gone or not functioning properly.
Inspect the gas cap. | Pressure-test the gas cap. | Install new gas cap if faulty.