Originally Posted by Arthur Dalton

Most purge valves trip a code b/c they get full of crap from the canister.
An easy fix is to clean it out with WD40 and hook it back up.
You can tell if it is working by holding it in your hand a feel for a heartbeat pulse. It will pulse on/off at idle with warm engine. It is between the intake and the charcoal canister, on left fender well and it is nothing more than a Switch-Over -Valve that allows engine vac to suck the tank fumes back into the engine vs being emmitted into the air [ emmissions device].
The ECU pulses the signal to it so the engine just grabs a little at a time, eliminating the possibility of a too lean condition.