P0455 code

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Gapafudus

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Hey guys I got another question. I got a P0455 code which is a emission leak, but I don't have a smoke test to see exactly where it leaks. Does anybody had this problem before? What did u do to fix it? I changed the gas cap and it's still there. Also a strange thing happens with my truck, not every time I drive it, but some times. When I am stopped at a light and then proceed to move, when I get at around 30 mph my truck makes a weird loud noise, like a roar or a growl, like it revs up or maybe even like a engine brake on a semitrucks. When I press the break and then press the gas pedal, the sound is gone. Any idea what this may be? It is an 03 Expy, 5.4L, 2WD.
 

Bedrck47

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P0455 - EVAP Control System Leak Detected (No Purge Flow or Large Leak)

Description
The PCM monitors the complete EVAP control system for no purge flow, the presence of a large fuel vapor leak or multiple small fuel vapor leaks. The system failure occurs when no purge flow (attributed to fuel vapor blockages or restrictions), a large fuel vapor leak or multiple fuel vapor leaks are detected by the EVAP running loss monitor test with the engine running (but not at idle).

Possible Causes


  • After-market EVAP hardware (such as fuel filler cap) non-conforming to required specifications
  • Disconnected or cracked fuel EVAP canister tube, EVAP canister purge outlet tube or EVAP return tube
  • EVAP canister purge valve stuck closed
  • Damaged EVAP canister
  • Damaged or missing fuel filler cap
  • Insufficient fuel filler cap installation
  • Loose fuel vapor hose/tube connections to EVAP system components
  • Blockages or restrictions in fuel vapor hoses/tubes (items also listed under disconnections or cracks)
  • Fuel vapor control valve tube assembly or fuel vapor vent valve assembly blocked
  • Canister vent (CV) solenoid stuck open
  • Mechanically inoperative fuel tank pressure (FTP) sensor

Diagnostic Aides
Check for audible vacuum noise or significant fuel odor in the engine compartment or near the EVAP canister and fuel tank.

Copied from the Ford Service Manual for a 2003 Expedition







 

Bedrck47

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Could be any one or more of the causes that I posted Time to start trouble shooting to find the fault or faults. I know that's not what you want to hear.

Hang in though others may chime in
 

Ed_Strong

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I have the same issue on my 2003 4.6L... I took the whole EVAP system apart and inspected everything (with the exception of the fuel tank related things as it is to hard to access but visual inspection didnt reveal any issues) The only thing i found out of the ordinary was the Vent Valve at the Charcoal Canisters was covered in crud which led me to believe it was either stuck open or stuck closed... I cleaned the whole system including that valve and put it back together but the code never cleared... I dont have the money for a new valve or to test with smoke machine so I left it as is. I couldnt test the vale operation under normal operation either to rule it out. EVAP tests and parts are expensive... I dont need emission testing where I live so I left it alone and I don't see a big hit on my MPG either!
 
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Gapafudus

Gapafudus

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Btw, how'd u take ur evap system off. I took the 3 bolts off, but I can't pull the damn thing out there. Anyway I try to pull it out something gets in the way.
 

Ed_Strong

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I do smell a faint odor of gasoline around the gas cap area after driving it and parking it in the driveway. If its been sitting for a while the smell goes away. I did buy a new Ford OEM gas cap but that did not work either!

To remove the Charcoal Canisters, if I remember correctly I had to disconnect all hoses and electrical connection, remove the 3 bolts and then had to rotate the tray while twisting it and pulling it down... it will only come out turning it vertically... it's very tight fit and looks like it wont fit thru the small opening but it does come out in one piece! I almost gave up on it when I removed mine!
I know it won't fully rotate and it won't turn fully vertical in place... but that's the best way I can explain how i got mine out!

Luckily it goes easier going in so installing it back was a breeze with the exception of the screws not wanting to fit back into their original locations, but even that wasn't too hard. Just put the screws back in without tightening them all the way first and you'll be all set.

I just saw that RockAuto.com has the whole EVAP tray assembly for $128.79 Ford OEM... not bad considering that buying all pieces separately will cost almost double or tripple that and from aftermarket sellers!
 
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