In this video I show how to perform a simple test to the evaporative emissions system to determine if the evap canister purge valve, aka vapor management valve, is stuck open. This test involves using a scan tool to command and monitor PIDs. These are the command pid for the evap vapor management valve, the command pid for the evap canister vent valve and the fuel tank pressure pid. With the engine running command the vapor management valve off. Then command the canister vent valve on. After that monitor the fuel tank pressure. There should be no drop in fuel tank pressure. Be patient. A management valve that is slightly stuck open will cause vacuum to build slowly. A management valve that is wide open will cause it to drop rapidly. If the fuel tank pressure drops this means that the purge valve is stuck open.

Note: The test shown in the video is only intended to test for a "Mechanically" stuck open evap canister purge valve. There are other factors such as circuit malfunctions or a faulty PCM that can cause the evap canister purge valve to stick open. Scanning for "circuit codes" is critical. Codes pertaining to the evap system that have the wording, short, open, high resistance, high and low voltage etc should be diagnosed and repaired first before doing this test as they can lead to false test results. Performing the test a second time with the purge valve disconnected can help to prevent false results in cases where there is a circuit condition but a code is not set.

Here is a link to the video showing how to test for a stuck open purge valve without at scan tool:    • Quick Easy Test For Stuck Open Evap P...  

Note: The information, to my knowledge, is applicable to the vast majority of gasoline powered vehicles post 1996. There may be variations from manufacturer to manufacturer. There may be many cases where this information will not apply and this test cannot be performed and or performed accurately. You will have to do your own research.

Use the information found in this video at your own risk. I make now guarantee off proper diagnosis using the information found in this video.

Disclaimer:

Barbour's Auto Help is not responsible for any damage or personal injury incurred in the process of performing any auto repairs done by you the viewer. Automotive repair is extremely dangerous. Repair your vehicle at your own risk. It is the viewers responsibility to verify all information and procedures as outlined in YOUR REPAIR MANUAL AND OWNERS MANUAL FOR YOUR VEHICLE. Owning and using a repair manual suited for your vehicle is essential for correctly and safely performing ANY repair to your vehicle. Always wear safety glasses, protective gloves and heed all instructions for use applicable to any piece of equipment you may use. Due to circumstances out of the control of Barbour's Auto Help, Barbour's Auto Help makes no guarantee that by the use of the information given in this video a quality repair will be made. Barbour's Auto Help makes no guarantee that the information provided is totally complete, synchronized and accurate. Verify everything using an appropriate repair manual. Verify everything with your own research.