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How to test EVAP Vent Solenoid

EVAP Vent Solenoid Operation

  • A Vent solenoid is a normally open solenoid that closes when energized and seals the system when the EVAP monitor is running a leak test.
  • The Vent solenoid is controlled by the engine control module (ECM) and is a simple on/off device
  • Most solenoids are ground side controlled

EVAP Vent Solenoid Testing

illustration of vent solenoid with  proper airflow
illustration of vent solenoid with  poor airflow, blocked filter
illustration of vent solenoid electrical test

Electrical Vent Solenoid Operation Test

  • Use a full functional scan tool with the solenoid plugged in to activate solenoid
  • If a scan tool is not available, unplug the solenoid and use jumper wires (preferably fused) to apply 12 volts from the battery positive terminal and ground from the battery negative terminal to activate the solenoid
  • Listen for the solenoid to click and make sure there is no flow between ports when solenoid is activated

Mechanical Sealing Vent Solenoid Test

  • Activate the solenoid multiple times using the electrical solenoid operation test and check that the solenoid is returning to the open state and is not sticking closed.

GoTech Tips


Tip : A Vent solenoid that sticks can cause EVAP venting system issues and set diagnostic trouble codes

Tip : It is common to have a filter attached to vent solenoid, a clogged filter can easily be mistaken for a stuck closed vent solenoid