[Shovelhd]

I keep getting a check engine light in my 2.0L non-turbo Jetta. Says the Evap purge valve stuck open. I replaced the valve with a Bosch. The light came back on so I took it to a shop and they replaced the valve again with a Dorman. I took it to another shop and they said the valve was in backwards, so they turned it around. The light stayed off for about 300 miles and came back on. I decide to do some troubleshooting. I've read that the valve should be normally closed, so I applied voltage to the original Bosch and the Dorman. They both open fine and close. I don't have a vacuum gauge but I couldn't blow through either when closed. Then I checked the voltage across the terminals at the connector plug, was reading 8.52 volts with the ignition on. I also moved the wires around when checking to see if there might be a loose connection. Seams to me like there should not be voltage there just because the key is on. From what I've read about Evap systems in general, the valve is only opened when there is a pressure buildup in the system/tank. What tells the ECM to open the valve? Seams to me like there should be a pressure sensor in the system, there's nothing like that listed in the VW parts diagram or in any of the parts sites for this model. I've seen fuel tank pressure sensors for many other cars but not mine. Anyone else had this issue? Any help would be greatly appreciated.

 

[woopsIfarted]

Hi I own a 2007 beetle and a 2009 jetta both with the 2.5 .I have replaced the purge valve in both with bosch. I learned the hard way to never top off the tanks after the gas pump clicks off. That will set off the light .My bug smoked after a major overfill and scared me. I thought it was a head gasket. 3 years later no codes.

 

[Shovelhd]

Thanks for the comments. I need to fill up the car so I'll reset the light and try not topping off the tank, then see what that does. That doesn't make any sense to me though. As I said in my original post, there seems to be voltage at the valve all the time keeping the valve open when the ignition is on. However I can't find a sensor in the system. Again, what tells the ECM to open the valve? If overfilling the tank is causing it, where is the sensor telling the ECM there is too much pressure in the tank? I just received an e-manual on flash drive in the mail today. Maybe something in there will help.

 

[woopsIfarted]

I hope so , I believe it opens about 10 minutes after starting. I'm shure the pcv system with purge valve only opens and after it reaches full temperature. Good luck. No other car I had was so sensitive to overfilling. German overengineering at its finest.

 

[AndreyPo]

Thank you for your answers. I'll try not to refill the tank then. I have the same problem

 

[woopsIfarted]

Welcome, Was the fix for my old habit, Ironic, it says do not top off on the caps .Shame on me.