On the A/C control side of the vacuum lines should there be a check valve some where in the lines?
Also how do you test to see if the fuel vapor management valve has gone bad?

Chris

 

I have two vacuum problems that i am trying to fix. One is the HVAC vents moving to defrost when i accelerate. The other is a check engine light caused by egr low flow. I have pulled a vacuum on all the lines. All will hold a vacuum except for the white line leading to the fuel vapor managment valve. I cant even pull 1" of Hg on that line.
I was able to find a diagram showing a check valve on the HVAC vacuum side. Where is the check valve located? This should fix my vent moving problem.

On the EGR code, i know it is being caused by a lack of vacuum. The only line that i can't pull a vacumm on is the line leading to the fuel vapor managment valve, located below the battery. How can i test this valve to see if it is working correctly?

Chris