service engine soon code P-0496 on 2006 Buick Rendezvous

Definition: EVAP flow during a non-purge condition. 661-Purge or vent solenoid failure; 662-Plugged EVAP canister condition; 663- Failed EVAP pressure sensor. Could you help me figure out what if any needs repaired-replaced.

by in Cuyahoga Falls, OH on December 26, 2010
1 answer 1 comment
ANSWER by on December 26, 2010
With so many codes, I would check to see if the purge valve is flowing, then check the vent valve and then see if the canister is flooded with fuel, in that order. This is Emissions Diagnosis, I do this in CA and it takes some skill and some training, or you will end up replacing parts that are expensive and not the problem.
COMMENT by on February 04, 2011
I checked the Canister and cleaned out all the fuels that are inside even the sensor. And still it has Engine light. what step do I need to do after all the steps that I did? please help.