The evaporation vent solenoid is an emissions system component that is commonly found on many road going vehicles. It is a part of the vehicle’s evaporative emissions system, which is designed to capture and recirculate evaporative emission from the fuel back into the engine bay. It is the job of the EVAP vent solenoid to allow air into the charcoal canister so that the EVAP system can pressurize and function properly. When the solenoid is opened, air is allowed into the EVAP system to relieve any pressure that may be present as a result of purging the EVAP system.
When the EVAP vent solenoid fails, it can prevent fresh air from entering the EVAP system, which can negatively affect the system operation. Usually a bad or failing EVAP vent solenoid will produce a few symptoms that can alert the driver of a potential issue that should be serviced.
1. Check Engine Light is on
One of the first symptoms of a problem with the EVAP vent solenoid is an illuminated Check Engine Light. If the computer detects an issue with the EVAP vent solenoid signal, position, or circuit, it may set off the Check Engine Light to alert the driver of a potential issue.
2. Pressure in the gas tank
Pressure in the fuel tank is another symptom of a problem with the EVAP vent solenoid. If the EVAP vent solenoid fails, it may not be able to properly vent and release the pressure from the vehicle’s fuel tank properly. This may result in excessive pressure building up, and then escaping when the fuel tank is opened.
3. Failed emissions test
A failed emissions test is another symptom of a possible problem with the EVAP vent solenoid. If the EVAP vent solenoid breaks or develops any vacuum leaks, it can hinder the operation of the entire system. This may result in a failed emissions test, which will have to be addressed before the car can be legally driven on the road.
The EVAP vent solenoid is an important component and any issues with it can cause problems with the vehicle’s emissions. If you suspect that your EVAP vent solenoid may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic. They will be able to diagnose any issues with your car and replace the evaporation vent solenoid if necessary.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Evaporation Vent Solenoid and was authored by Ed Ruelas.