I own an '04 Avalanche. It recently failed an inspection. Engine light came on with an OBDll code PO446. Was wondering if any of you out there has had this problem and if so were you able to figure out the source of the problem. Any expertise in this area would be helpfull. Thanks.

 

Here is a link to a list of codes.
http://www.obd-codes.com/trouble_codes/

 

generally with that code the vent valve has allowed in to much road debris and dust and dirt pluggin the canister replace the vent calve and the canister and code wont come back