Why did my check engine light come on after getting gas?

A check engine light that comes on right after you fill up with gas is most often caused by a gas cap that was not tightened fully or has worn out, which lets fuel vapors escape and triggers an EVAP system code. Overfilling the tank past the first click can also flood the EVAP charcoal canister and set off the light. The first step is to make sure the cap is on tight and clicks several times, then drive for a day or two to see if the light clears on its own. If it stays on, you may need a new cap or there may be a leak elsewhere in the EVAP system. At Motoro Cars in Miami, our ASE-certified, AAA-approved technicians use computerized diagnostics and smoke testing to confirm the source. Call Wynwood at (786) 634-2002 or Doral at (786) 633-3220 if the light persists.