Problem with the check engine light on a Mercedes E-Class

For the check engine light, start by checking if the gas cap is properly tightened, as a loose cap can trigger the light. If the light remains on, consider using an OBD-II scanner to read the error codes, which can help identify the issue. Regarding the registration, 'Essence' is another term for gasoline, so you should select 'Gasoline'. Let me know if you need further assistance or if the check engine light persists after these steps.