I've been getting the P0455 code for a while now and so I decided to take a crack at tracking it down. I build a smoke tester with a propane regulator, some hose fittings, one gallon metal paint can and used incense for the smoke. Hooked it up to my air compressor and to the hose that connects to the rear of the purge valve to find smoke pour out of a hole in the bottom of the cruise control unit. Is that supposed to happen or did I just find my leak?

 

Actually, it's not the cruise control. It's the little canister beside it.

 

yeah, that is the filter canister for the EVAP system (#3 in the EVAP layout below). You need to somehow seal it up, i'd recommend a latex glove or something like that. Then re try your smoke test.

 

Thanks for the tip. I managed to close that off and retest but didn't find any major leaks from the valve to the back.

I've already replaced the gas cap so I guess the next thing to try is the purge valve. I guess it could fail without throwing any codes.