Randy Tice

My CE light is back, we had the codes pulled from a local parts store, we had a P0405 and 2xP0455s. I have replaced the EGR (P0405), the gas cap, and the EVAP solenoid (P0455) but the CE light persists and the code continues to be a P0455. I'm not sure what else to try, looking for help. I'm guessing some sort of test on the evap lines themselves but I don't know where to begin.
Thanks

tech2

p0455 set due to a large evap leak
the test runs as such:
with the engine running the pcm closes the vent valve to seal the evap system, it then opens the purge valve which allows engine vacuum to draw vapours out of the evap cannister. for the test to pass the fuel tank pressure sensor must achieve a set amount of vacuum and hold that vacuum.
-if any of those things don't happen a fault is set
check these things:
-verify the vent solenoid valve is closing to seal the system
-verify the purge valve solenoid is opening
-view the fuel tank pressure sensor with enging off and fuel cap off...should read 0"h20
-install the fuel cap and start the engine, open the purge valve with the scan too and close the vent valve....the vacuum parameter should draw into a negative reading...open the fuel cap and the reading should go back to 0"h20