It sounds almost too simple to be true, but one of the most common reasons a check engine light comes on is a loose, damaged, or missing gas cap. Before you worry about an expensive repair, it is worth understanding how such a small part can trigger that warning, something many Columbia drivers are surprised to learn.

Your vehicle’s fuel system is sealed, and part of that system, known as the evaporative emissions system, prevents fuel vapors from escaping into the air. The gas cap is a key part of that seal. If the cap is not tightened properly after fueling, is cracked, or has a worn rubber gasket, the system detects a leak in the seal and turns on the check engine light. It is the vehicle’s way of flagging that vapors may be escaping.

Often the fix is as easy as tightening the cap until it clicks or replacing an old, worn one for a few dollars. After the cap is secured, the light may take a little time and some driving to reset on its own. That said, the same evaporative system can develop other leaks, so if a new or properly tightened cap does not resolve the light, the cause lies elsewhere and deserves a look.

At Exhaust Plus in Columbia, we can determine whether a simple gas cap is behind your check engine light or whether something else is going on. If your light is on, stop by our Columbia shop and let us check the simple things first.