P0455 in 07 Suburban 5.3 question

[Mattt]

I searched and read quite a few threads here about code P0455 and it seems like most of the existing threads are having to do with '06 and older trucks. I have an 07 new body style Suburban with a P0455 that won't go away. Tried gas cap but that made no difference...came back eventually. When I turn the CEL off with my handheld it stays off for a while, but the I/M readiness for Evap System Monitor takes forever to go "ok." I suspect once the Evap System test finally runs and flips the I/M to ok, that is probably when the CEL comes back on.

 

I see there are only a few things that trigger P0455. Is there a way to isolate which of the options are causing the CEL to come on? I don't see any obvious leaks, broken hoses, etc but I haven't gone over it with a fine tooth comb yet. It sounds like it could be the tank vent solenoid, but I've never been one to just start throwing parts at a problem. Is there any way for a skilled home shop guy to figure this out without owning a GM Tech 2?

 

Thank you in advance!

[txab]

http://www.gm-trucks.com/forums/topic/104569-the-evap-system/

 

 

https://www.google.com/search?as_q=p0455&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=www.gm-trucks.com&as_occt=any&safe=images&tbs=&as_filetype=&as_rights=

[Mattt]

Thank you for the link....already read most if not all of those threads. As I mentioned they all are addressing 06 & earlier vehicles. I'm looking for more and better info for 07+ Suburban, Silverado, etc.

[wheelsthatgrip]

I had the same exact issue with my 08 Silverado (I too tried the Gas Cap). In my case it was a defective Evap Vent Solenoid. I was able to save a few bucks by using a lower cost Dorman replacement part.

 

I took an ohm meter to the old soleniod, coil was completely open.

 

Keith

[Mattt]

I had the same exact issue with my 08 Silverado (I too tried the Gas Cap). In my case it was a defective Evap Vent Solenoid. I was able to save a few bucks by using a lower cost Dorman replacement part.

 

I took an ohm meter to the old soleniod, coil was completely open.

 

Keith

Thank you for the suggestion. When you say you took an ohm meter to the old solenoid, and the coil was completely open....can you give a little more explanation what/how you tested? I believe the Evap Vent Solenoid is in the back almost above the spare tire? I know the vent from it goes up the fill pipe(zip tied to it) but I haven't pulled the spare down yet to get a really good look. Any chance you have the Dorman part # for the replacement? Thank you in advance.

[wheelsthatgrip]

I used a Digital Volt Ohm Meter (DVOM) and checked the resistance acoss the two pins of the Evap Vent Soleniod. The was zero resistance, this would indicate an open coil. If the coil is open, the valve won't close resulting in a pressure leak in the evap system (Always Venting). You should check the Dorman Website for you application. I often go to Rock Auto , they have good pictures and good replacent alternatives.

 

Here is a video of your exact vehicle

 

Keith

[Mattt]

Sweet....thank you for the info and the link.

[Mattt]

Moving this back up to see if I round up any part numbers for exact fit replacements. I have tried 2 different replacement solenoids from my local Autozone and neither one worked. The GM dealer replacement part # 20995472 requires a jumper harness because the jackholes at GM changed the harness plug on the new part. So that makes it an almost $150 part replacement.....~$100 for the vent solenoid plus ~$40 for the jumper harness.

 

Option one from Autozone was Wells part # PV485 and was completely wrong. Option two from Autozone was Wells part # PV483. PV483 looked exactly the same as the factory part but the wire harness connection is a different shape. I haven't found anyone local that carries Dorman parts.

 

Is there ANY part out there available that is an EXACT replacement for plug and play install?

 

Is there ANY way to test the Evap system and make sure this vent solenoid is malfunctioning without going to the dealer for $125 diagnosis? I hate to throw parts at it without knowing this is the root cause.

 

Any additional info, opinion, part #'s for replacements, or diagnosis tips are greatly appreciated! Thank you in advance.

[Mattt]

One more question for the road.....is there any other GM, Chevrolet, GMC, etc vehicle that uses the same Vent Solenoid? I have tried cross referencing this and have come up empty handed.

I am asking this because there are at least 5 pick your part junkyards within 15 miles of me that I could possibly get one from another vehicle from. These 5 yards never have '07 or newer Suburbans, Tahoes, etc though so I'd have to get the part from another vehicle that also uses the same part.

 

Thanks in advance.

[txab]

The wiring harness is available on ebay for about $18 shipped. You can buy the vent for around $50 several places

[Mattt]

I haven't been able to find the vent solenoid for ~$50. Can you point me in that direction? Thank you.

[txab]

Ebay , Rockauto, etc..... Using the number you posted

[Mattt]

Well, I put a new evap vent solenoid in, cleared the code, drove it over the weekend, and the CEL came back on today. Same code.....P0455. I'm out of ideas......anyone know what to check next? Frustrated......

[rusty503]

I used a Digital Volt Ohm Meter (DVOM) and checked the resistance acoss the two pins of the Evap Vent Soleniod. The was zero resistance, this would indicate an open coil. If the coil is open, the valve won't close resulting in a pressure leak in the evap system (Always Venting). You should check the Dorman Website for you application. I often go to Rock Auto , they have good pictures and good replacent alternatives.

 

Here is a video of your exact vehicle

 

Keith

 

You have this backwards. If you measure across the terminals and read zero ohms or very low ohms the coil is most likely GOOD. An open coil would show as infinite ohms.

[silveradoprime]

You probably have fuel in your evap canister, and also check to see if your vent line from the engine to the canister isn't plugged up