Nissan Altima persistent loose gas cap warning light causing check engine light issue on Nissan Altima

Some Nissan Altima owners report experiencing a persistent loose gas cap warning light that can trigger a check engine light issue. This warning is typically indicated by an illuminated light on the instrument panel, suggesting that the fuel cap is not properly secured. Even after resealing the fuel filler cap, some owners find that the warning light remains, which may necessitate a new fuel cap or investigation into a potential EVAP system leak. While it is safe to drive with this warning, prompt resolution is important to avoid poor engine performance and decreased gas mileage. The check engine light can also activate due to a loose gas cap, which causes the fuel system integrity test to fail by disrupting the vacuum condition in the engine's fuel system. Common causes for this warning include a missing gas cap, which is the leading reason for its illumination, as well as a damaged or bent fuel tank neck that may prevent proper sealing of the cap. Addressing these issues is essential for maintaining optimal vehicle performance.