Had code p0456.....repaired 2 cracked lines at the Vapor canister. also replaced solenoid purge, after 120 mile engine lite comes back on, did a fog test all was good. rest computer engine lite came back on. have a 2003 4.7 sxt. thanx for any input....

 

what were the new codes???????

 

same code....PO456

 

you should also check the evap lines under the hood, (running past the battery area, look for a green cap) and the gas cap (yes it can cause the code if its bad)

 

I have replaced all the lines at the canister and the canister purge sensor and lines there as well. new gas cap, still getting PO456 code, one step further did a fog test with no leaks.......

 

did you try resetting the pcm?

 

i did when the code first came up about 2 months ago.....and did it again 3 weeks ago and 300 miles later lite came back on did a obdII test again same code PO456......thanx for your help

 

But did you replace the gas cap with a non-vented one?

 

yes i did.....non vented cap

 

Could be a bad line going to the purge valve from the caniser?