Mercedes-Benz 420SEL Evaporation Vent Solenoid Replacement at your home or office.

What is the Evaporation Vent Solenoid all about?

Your vehicle is equipped with an evaporative emissions control system that effectively controls fuel vapors produced in the fuel tank. It processes them through an emissions control canister, or charcoal canister, and then vents the vapors to the engine to be burned with the air/fuel mixture. In the evaporative emissions system, a series of valves controls the flow and allows for diagnostic testing by the engine control module. The vent solenoid, or vent valve, performs the function of introducing clean air into the evaporative emissions system to carry the fuel vapor to the engine. The vent valve closes when the engine control module commands it to for the purpose of leak tests. When the vent valve is closed, the evaporative emissions system is pressurized and tested for leaks. If it is sealed and no pressure is lost, the test passes. If the pressure drops, the engine control module assumes a leak is present and turns on the Check Engine light.

One of the most common failures in the emissions system is the vent solenoid. It can stick open, causing the engine control module to think a leak is present, or it can stick closed. A closed vent valve can make refueling difficult as the pressure in the fuel tank isn’t vented. The fuel nozzle will click off constantly, making it tedious and frustrating to fill your fuel tank.