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.

Keep in mind:

• An evaporation vent solenoid code could be related to a loose fuel cap.

How it's done:

• The evaporative vent solenoid is inspected to verify that it needs replacing
• The defective solenoid is removed
• The new solenoid is installed
• The engine is scanned for codes
• The vehicle is road tested for proper operation and that no Check Engine light comes on

Our recommendation:

The vent solenoid is prone to failure from dust and dirt in the environment such as gravel roads, and will require replacement sooner than if operated only on pavement. If the fuel tank is difficult to fill or the Check Engine light has been diagnosed as a vent solenoid failure, you will need one of our expert technicians to replace the evaporation vent solenoid.

What common symptoms indicate you may need to replace the Evaporation Vent Solenoid?

• Check Engine light is on
• The fuel tank may be hard to fill as the fuel nozzle can click off prematurely

How important is this service?

The vent valve is an important diagnostic solenoid for the evaporative emissions system, however the associated symptoms are more of a nuisance than a safety or operating issue.