donbrew

EVAP codes can take 2 weeks to re appear after clearing them.
There are other reasons besides "gas cap" for P0440.

I will say it again: P0449 is a fault in the CIRCUIT. It does not mean that anything is operating out of spec. Could be the wrong valve that fits and works, but has more/fewer windings etc.

donbrew

The 2006 model HHR has different wiring harness to the valve than the new replacement part. A new pigtail must be purchased and installed correctly to hook it up.

Any chance this fact has a bearing on the story?

I could never find out what "normal operation" means exactly when I was running live data on the EVAP system. Could you please post the info for me?

jdieter

I used the original connector on the vent valve and repaired a broken wire going to it. Both before and after the repairs with the two codes still current, while doing a test drive and live data monitoring the evap purge command and the fuel tank vapor pressure, the vapor pressure was always saturated no mater what % the purge command was. After the trip to the dealer and they finding(p0440 that my reader didn't catch)/fixing the gap cap issue, I ran the same live data drive test and the tank vapor pressure responded to the purge commands. With these empirical results and no cel I reasoned the evap system is operating normally.

donbrew

Now there is no CEL? I am getting confused. If there is no CEL then the codes you see are pending, not current.

If you did not have to change the pigtail then it had been replaced before. The replacement part requires a different connector than the factory harness. Which would explain the broken wire, but what about the other wire? Maybe a bad solder or not soldered causing a bad signal?

jdieter

All codes were cleared after the dealer service, and none have reoccured. Owned the car since new and pigtail never replaced.

rafterman191

With ignition ON, should a test light not pass from A to B? Or is the grounding via PWM causing this connection to be more complicated than that?

donbrew

The only real way to check it is with a tech2 or similar scan tool. You have to command the vent valve to 50% to get a test light on.
purge valve is N.C.
vent valve is N.O.