I have had a CEL come on occasionally with the code P2422. Other traits associated with this CEL is I wasn't able to start the car after filling it up one day and the transmission shifts crapped at low rpms. The P2422 CEL is Evaporative Emission System Vent Shut. Being a literal person I assumed that this meant for sure that the solenoid back by the charcoal canister was stuck closed. I got into the wheel well one day and tried to remove the solenoid but wasn't able to (not sure if it can be separated from the charcoal canister) so I vacuumed the inlet to it and pulled the clip off and put it back on and after driving the car for a couple of days the CEL went out. This occurred months ago. The CEL came back on again last week and I remembered advise from one of the forum members that it could be the purge valve and to listen to it and see if you could hear it ticking. If not remove it and clean it with WD40. So I listened to it and couldn't hear it. So I gave it a rap with a handle on a screw driver and the idle dropped down then recovered and it sounded like it started ticking. The car started shifting smoother and today the CEL went out.

My takeaway from this is
a) it is a hell of a lot easier to check the purge valve than to get into the rear wheel well so if you get this CEL check the purge valve first.
b) I think that the fact that the CEL went out after I monkeyed around in the wheel well was just a coincidence and didn't really do anything and honestly at the time I couldn't see how what little I did could have fixed anything so see a) above.
c) I think that both times I got the CEL was after running the car pretty low on fuel. I suspect that the purge valve may be getting moisture in it causing it to hang up. Just a hunch.

 

My son 2008 C350 had CEL off & on. The mechanic said that it's generic error. Could you point me : where is the purge valve so I can spray some WD40. Thanks.

 

https://www.pelicanparts.com/techart...eplacement.htm