Fault Code P0455 Evap System Large Leak

[97boxsterred]

I have a 2005 Cayenne V6 with about 52K miles. I got this check engine light and checked the fault code, it was P0455 EVAP SYSTEM LARGE LEAK.

I reset it and it came back on a few days later. Can someone help me with this one.

[Loren]

P0455 Evaporative Emission System Leak Detected (large leak)

Possible cause of fault

- Tank cap not tightened correctly, faulty or missing

- Mechanical fault in EVAP canister purge valve (does not close fully)

- Leakage diagnosis pump leaking internally (membrane) or externally

- Mechanical fault in EVAP canister shutoff valve (does not close fully when power is supplied)

- EVAP canister shutoff valve connections leaking

- Tank system (including pipes) leaking

Check your gas cap and seal.

There have been some changes to the gas cap so you might want to make sure you have the latest revision.

[Doug_B_928]

I'm having this fault in my 2008 Cayenne S, with the addition that Durametric says under the fault "No signal/communication." Is there a way to check the integrity of the gas cap, or do people tend to just replace it to see (it's about $40 CAD at the dealer)?  Also, I had the car at the dealership about a month ago where they changed the injectors. Are any of the items in the list above under or near the intake such that this could be cause by something that the mechanic left loose?

 

 

Edited May 27, 2017 by Doug_B_928
added some additional info about the code

[JFP in PA]

Yes, the gas cap can be pressure tested with the right equipment.  It is impossible to even guess what may have been left loose when the injectors were done, that would need a smoke test.

[Doug_B_928]

Thanks, JFP.  I put my mity vac on it with an attachment that fit inside the inner diameter of gas cap.  I put pressure on it and it didn't hold, but I'm also not sure that this is the correct location to be testing.  Is this the kind of equipment and test to which you were alluding? 

[JFP in PA]

16 minutes ago, Doug_B_928 said:

Thanks, JFP.  I put my mity vac on it with an attachment that fit inside the inner diameter of gas cap.  I put pressure on it and it didn't hold, but I'm also not sure that this is the correct location to be testing.  Is this the kind of equipment and test to which you were alluding? 

 

 

Stant and several other tool companies make them:

 

[Doug_B_928]

Interesting, thanks.

[Doug_B_928]

Turns out the dealership had left the line loose that goes from the vacuum pump to the intake (it was loose on the intake side).

[Loren]

14 minutes ago, Doug_B_928 said:

Turns out the dealership had left the line loose that goes from the vacuum pump to the intake (it was loose on the intake side).

 

Glad you got it sorted.