In either case, once the issue has been resolved, you may need to drive your Sonic for a few miles to allow the onboard computer to reset itself and turn off the check engine light. If the cap is damaged or worn out, it may need to be replaced. If you suspect that your gas cap may be the cause of the problem, you can try tightening it to see if the light goes off. This can trigger the vehicle’s onboard diagnostic system, which may illuminate the check engine light. The fuel system in modern vehicles is designed to maintain a certain level of pressure, and if the gas cap is not sealing properly, it can cause a leak and disrupt the pressure balance in the system. It is possible for the check engine light to come on in Sonic due to a loose or bad gas cap. When this happens, the engine should be turned off immediately to prevent further damage. The flashing light often indicates a misfire, which can cause damage to the catalytic converter.
The vehicle can typically be driven safely for a short period of time, but it should be taken to a mechanic soon to avoid further damage or increased emissions.įlashing CEL: When the check engine light is flashing in Sonic, it indicates that there is a significant problem with the engine that requires immediate attention. Static CEL: A static check engine light in Sonic means that there is a problem with the engine or emissions system, but it is not an urgent issue.