FIXED! P0455 - 2017 Honda Pilot, 60k miles

Mikerizer

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Make
Honda
Model
Pilot
Year
2017
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60k +
Engine
3.5
:fixed: P0455 EVAP System (Very) Large Leak Detected

I looked around in the engine compartment...the air filter housing wasn't seated and locked in properly. I buckled it up, and I didn't find any other visible leaks on an eyeball inspection. I cleared the codes and the PO455 came back a few days later.

This is my daughter's car.

What should I look for in troubleshooting? THANKS!
 
Last edited:

grcauto

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Your evap has nothing to with the air filter or intake.
It's the system that purges the fuel tank fumes. Everyone replaces the gas cap but if the cap is not cracked and threads are not corroded I wouldn't waste my time and money on that. The system is plumbed from the top of the tank to the canister and from there to the intake through the purge valve. There's also a vent valve. May need to smoke the system to find it.
 

grcauto

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I would test the purge valve. You put it under a vacuum and if it don't hold that's a source of a large leak.
 
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Just to throw this is in. I've had people that had their vehicle running while fueling up. This can throw that evap code also. Cannot have vehicle running while gassing up. Some people have a bad habit of it especially if too hot or too cold outside. Anyhow, hope this helps.
 

Mikerizer

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I haven't really had time to dig into this one, but the other day, she stopped for gas. After she filled up, the CEL went off for a day or so, and came back on. I'm wondering if the "gas cap" (it doesn't have the traditional cap; the fuel cover encapsulates the filler neck) has some kind of defect? What should I look for here?
 

billr

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Look for crud or corrosion, any roughness, on the fuel-fill pipe; where the cap has to seal. The cap itself will have some kind of soft (rubbery) seal; check that it isn't cracked or otherwise damaged and that it still feels soft and "springy" enough to have a chance of sealing.
 

grcauto

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Use a scotch brite pad and clean the threads on the cap and filler neck. Apply a film of grease to the surface of both. That should be a good seal.
 

nickb2

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After she filled up, the CEL went off for a day or so, and came back on.
Hi mike, just to bump, if cell light is coming on and going off, not a evap code. B y law evap codes are hard ones.

So I am going sherlock holmes here, if cell is going on and off, not na hard code, suspect something else.

wink wink

 
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