06 tahoe small leak detected code

[Mudsport96]

Ok, 06 L59 Tahoe. My wife sent me a message about the engine light being on this morning. Because we work such completely opposite shifts and I work 12s I usually dont get to see her or the Tahoe through the week. So I got her a scanner and showed her how to use it.
She said it was showing small emissions leak detected... but didnt get the DTC number before she cleared it. So I looked it up and it could be p442 or p456. Anyone know the difference one is small emissions leak detected and the other is
emissions leak detected (small).
Anyone deal with this before? And since I will only get one day to look at it, any advice where to start?
Edit, the fuel cap usually come up on the display as tighten cap so i dont imagine that.

 

[OR VietVet]

The first step is to hopefully have the EXACT code but in this case use the two codes you looked up and go thru what those say about diagnostics and likely causes of those codes. The reason ANY code steps start out with likely causes is that, like TSB's, these can be pattern failure points to look at first before going off helter skelter.

 

[Mudsport96]

Right right. Troubleshooting isnt to much of a problem, that's my daily job lol. I was just hoping for a " Been down that road look here " type of deal.
Was able to get the Google to help searching this forum( since I cant seem to get the search feature here to work for me lol). And someone had a thread several years ago with a picture of the evap hose rubbed through by the intake cover. Hopefully it's as simple as that.

 

[OR VietVet]

Hope so too. Good luck.

 

[Mudsport96]

Hope so too. Good luck.

Thank you, going to need it after 70 hour week in the heat.

 

[OR VietVet]

Reminds me of my younger days when I was turning wrenches for a living and in KC, Mo. it was hot and humid and after work I was working on other people's cars for extra money and sometimes was turning wrenches 7 days a week and drinking a lot of cold beer on the weekends. I do not miss that at all!

 

[Mudsport96]

As of right now, the light hasnt come back since she reset it Wednesday. I'm still going to look it over tomorrow but crossing my fingers that it was a fluke.

 

[HiHoeSilver]

As of right now, the light hasnt come back since she reset it Wednesday. I'm still going to look it over tomorrow but crossing my fingers that it was a fluke.

Usually a good sign of a fluke problem, but a fluke problem often develops into a real one. Did you ever see the exact code?

 

[Mudsport96]

No I havent, was hoping it would come back by today so I could figure it out, but no luck. Since it will be next weekend before I can look at it again, theres a chance it will pop the light on again. Then I'll have 2 days to look at it since it's a holiday weekend. From what I've had time to search since I've posted, its probably the vapor canister or purge solenoid going bad. When I get it resolved, ill make sure to follow up the thread and let everyone know.

 

[Rocket Man]

It’s usually a leaking gas cap, purge solenoid, vent solenoid or vapor canister. If I was you, I’d order everything and replace all 3. That’s what I ended up doing with mine, only I did one at a time. They’re not expensive all together.

 

[Mudsport96]

Probably what I'll end up doing. I think the cap may have been changed already, it's not yellow like a Flex vehicle should have. And if it's a cheap store brand one that may be the place to start anyway.

 

[zbad55]

The P0442 and P0456 codes are for a "Small"Leak in the EVAP system, the other common code s the P0455 which is a "Large" leak code. As mentioned you can check the usual components but I would drive it for awhile and see if it comes back on.The small leak code needs to have (2) fails in order to set the dash light. Make sure that there is not any rust on the filler pipe sealing surface for the cap, that is a common cause of most evap codes,

 

[retiredsparky]

It would make sense that a leak code for the vapor system would be a device that can allow pressure to be relieved in the system. The three devices that can do that are the two solenoids and the gas cap. Usually when the canister fails, the tubing either plugs up with loose charcoal bits or a solenoid valve hangs open due to the particles building up inside the valve, preventing it from opening or closing completely.

Changing solenoids without doing the canister can sometimes result in not fixing the problem, since it is the loose charcoal from the canister that are messing with the solenoid operated vent or purge valve. That said, gas cap sealing problems are not uncommon. A rag with some Techron or other cleaner wiped around the inside of the gas filler can be a good starting point.

When changing the solenoids it is a good idea to blow out the tubing with low pressure air before connecting up the new solenoids.