Mercury Mariner check engine light intermittently on after oil change with potential dash system repair needed on Mercury Mariner

Some Mercury Mariner owners report experiencing intermittent check engine light issues after an oil change, which may indicate various underlying problems that could require dash system repair. These issues can stem from factors such as an incorrectly seated dipstick, a backward oil fill cap, low oil pressure, excessive oil in the system, the use of the wrong oil, or a sensor that hasn't reset. Additionally, if the fuel tank was filled after the oil change without properly securing the gas cap, this could also trigger the check engine light. Owners are advised to ensure the gas cap is tightly secured and to wait a few minutes after starting the engine to see if the light resolves. In some cases, like with a Toyota Camry, a loose mass airflow sensor connector was found to be the culprit, which was fixed by cleaning and replugging the connection. If the check engine light remains intermittent after addressing these common causes, consulting a mechanic or automotive expert for further diagnosis may be necessary to ensure the vehicle functions properly.