P0441 and P0455 Evap Code help

All

I have been chasing P0441 and P0455 code for a few months. I have replaced gas cap, tested purge valve with truck on and it calling for purge and felt the vacuum. I also disconnected the connector and verified no suction.

I have smoke tested from the purge valve back to the canister with the truck off and found no smoke bedsides at the vent near the cap.

Not sure when the canister air inlet should be closed but I pinched the air inlet line from the filler neck off a decent amount not all the way but evap pressure did not change.

Is the next step to replace vapor canister? My evap pressure is still at atmospheric pressure when it’s calling for 100% purge it never changes.

 

Have you verified the purge valve opens when commanded and there is no vacuum present at the port with the engine running and the valve unplugged.




For smoke/pressure testing you have to cap off the fresh air line, closing the vent VSV will not seal the system.

 

Yes I verified the the purge valve opens when it’s commanded too and the electrical connector unplugged it does not leak by.

I will try to test with the smoke again and pinch off the vent valve line.

Does the pressure reading of 14.5 psia seem too high? The pressure never changed even when the demand for purge valve was 100%. I did try to pinch off the Vent Valve when the truck was running thinking it was stuck open but I didn’t get the best seal pinching but the pressure never changed.

 

It may be a little high depending on your elevation but it definitely should change with pressure changes in the system.

 

oh ok. I’ll try smoke tested either again. In in SE PA so we are pretty low elevation.