On my 03 Civic I get CEL with P1457 Evap code. I reset it and it came back after driving about 200 miles. I have ordered Honda OEM Gas Cap and I will replace it to see if that takes care of the problem. People are talking about several valves and canister etc; Instead of replacing one valve at a time, do you know if you buy whole canister it comes with all valves etc? I'm getting this done by a mechanic and don't want to go back and forth and every time he charges me by the 1/2 hour, one hour. Any thought on what usually is the problem with this kind of code? Might just get lucky replacing the usual suspects. I know smoke test is the way to go, which should pint point to where the leak might be coming from.

 

Yes do a smoke test to determine where the EVAP leak is.

Most common cause of the P1457 code is a faulty By-pass canister shut valve (CVS). Replace the EVAP canister as well since it will likely be rusted together with the CVS valve. Personally, this colved my P1457 issue on my 03 Acura EL 1.7L (same as Civic).

 

If you buy the whole canister, the CVS comes with it. Correct?