Hi everyone:) yes it has been a while. Before I proceed, I would like to thank everyone who responds to this thread and my apologies if I miss anyone. Ok here is the deal: 2006 Chevy HHR LT with the 2.4L. 140,000 miles on it. Been having a check engine light come in. Pulled the code and get the dreaded P0446. This is an EVAP issue. So this is what I did: Replaced the charcoal canister underneath the car, replaced along with the new pigtail connector, the vent solenoid under the hood, and put a brand new gas cap on the car. I cleared the code and drove the car. All monitors passed at which time the car passed inspection. This all happened in October. Now it is December. I put probably 300 miles on the car. The CEL came back on. Checked the code and I get the P0446 again. Now I am totally confused. Why on earth would I get that code again? The car is in immaculate condition and is babied by me. Garage kept. Does anyone have any idea why I am still getting code? What am I missing? I have not tried a smoke test but then again I do not own an instrument that will force open my evap system to run smoke through it. Any help would be greatly appreciated. Happy Holiays to you all.

 

P0446 means there is an obstruction in the vent system.

A clogged charcoal filter; the media inside the canister.
A bent/kinked vent tube. From the valve to the top of the filler pipe.
A clogged/stuck valve.
A stuck closed purge valve.
A bent/kinked EVAP return pipe.

From a post by Donbrew in another thread .

When you changed the canister vent valve you put the seal on from the old valve?
What parts did you use, I’ve been stung with crap of shore junk from EBay and Amazon before. The under hood valve failed after 3 weeks! Try the blow through test .

 

Thank you for responding and how the heck have you been buddy!😁. In your response you mentioned filler tube. Do you mean the fuel tank filler neck?

 

P0446 is a BLOCKAGE in the EVAP system. My guess is the vent valve on the charcoal canister is bad.
It means the vacuum in the tank is too high. Could be vent valve stuck closed, the purge valve stuck closed or the tank pressure sensor malfunctioning. The purge valve(under hood) is normally closed, the vent valve is normally open.

Does the automatic shut off at the gas pump acting funny? That would be a clue pointing at the vent valve.

 

I’ve been doing ok, considering. But as Donbrew asks , do you try and squeeze in a bit more at the pump? Does the auto shutoff work normally?

 

I hope both of you guys get my response. I tried to reply separately but couldn't. Don, when you say vent valve, do you mean that large box shaped part under the car that the charcoal canister is attached to? And to answer both of your question about pumping gas, I do not remember if I squeezed in extra. It's possible but I don't think so. The pump is not clicking. Working normally

 

V marks the valve, CHAR marks the charcoal canister.

 

Ok ok gotcha I understand. The V is replaced. The charcoal I did not. Should I replace the charcoal?

 

When you replaced the “V” did you make sure to swap the rubber seal over from the old “V” ?

Sometimes the canister gets clogged up!

 

At first, I forgot it then remembered and went back outside and swapped that plug over lol. So yeah it is on the car currently.