P0446 Then P00455

[borrone821]

Sirs,

I originally encountered a P0466 evap code, where I disconnected the lines to the vent valve, blew them out with my compressor, and cleared the code. All was well for a few days, then I tripped a P0455 code, which is a large evap leak. I'm assuming these are related and I screwed something up.

 

First off, gas cap is tight. I checked all the lines and they seem fine. Where else can I look?

 

thanks

Jim

[dynobuzz]

Sirs,

I originally encountered a P0466 evap code, where I disconnected the lines to the vent valve, blew them out with my compressor, and cleared the code. All was well for a few days, then I tripped a P0455 code, which is a large evap leak. I'm assuming these are related and I screwed something up.

 

First off, gas cap is tight. I checked all the lines and they seem fine. Where else can I look?

 

thanks

Jim

 

 

If you don't have any leaks your evap vent valve itself might be bad...I just replaced mine on a 2006 gmc...how did you clear the code the first time?...if you did so by disconnecting the battery all that does is reset your pcm but after it runs 3 tests and the problem is still there the light will come back....

[gmtech121]

vent valve won't cause a p0446. Pull off the hose to the purge valve on the upper intake on the tank side and disconnect the electrical connector with the vehicle running. Bet you have vacuum there or possibly intermittantly. $10 says it's a stuck open purge valve.

[minibike132]

vent valve won't cause a p0446. Pull off the hose to the purge valve on the upper intake on the tank side and disconnect the electrical connector with the vehicle running. Bet you have vacuum there or possibly intermittantly. $10 says it's a stuck open purge valve.

 

 

Correction, vent valve will cause a 446. It still could be a purge but a stuck closed valve or clogged vent path causes lots of p0446's.

 

Checking the purge is as easy as pulling the hose and connector though so it's an easy check first.