The Best Bad Gas Cap Check Engine Light 2023. A gas cap that cannot seal can cause an evap system leak. Web but it's true!

Web if the check engine light is still on after tightening the gas cap, then it means the gas cap is too loose and not forming a tight seal in the fuel system. A hissing noise coming from the gas tank area Another approach is to purchase an obd (onboard diagnostics) reader for about $75 and plug it into your vehicle's obd port (usually found under the dash, just below the steering wheel).
