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Engine light on a Mercedes due to a loose fuel cap.

Model: Mercedes Classe C W205 - Years 2014-2021
Part: Fuel cap

The video shows a very instructive case, which can occur with some frequency: a Mercedes enters the workshop with the engine light on: connecting the diagnostic tool, the fault code P0442 is read, indicating a small leak in the EVAP system. The EVAP (Evaporative Emission Control System) is designed to prevent gasoline vapors from escaping into the atmosphere, and a common cause of this error is the fuel cap not being properly tightened: in fact, the mechanic notices that the car has just been refueled; he notices that the cap is loose: the "repair" simply consists of screwing it on properly, until it clicks. After tightening the cap, the fault is cleared with the diagnostic tool, and the light turns off. So we remember: if something like this happens after refueling, we know what it is.

Posted on 23 August 2025 by ScegliAuto

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