Jump to content

P0455 Evap Leak

Coop8202
 Share

Recommended Posts

Coop8202 Enthusiast

Coop8202

Posted
Posted

Hi, I have a 2008 GMC Sierra with the 5.3. I got a P0455 Evap code a while back. I can clear it but it comes back within a few days. When filling the truck up, when the pump shuts off gas spews from the canister area underneath the truck. I can usually always smell a raw fuel smell after driving from the bed area. Thanks! 

sefiroxx Enthusiast

sefiroxx

Posted
Posted

Check hoses and canister. The system should be sealed. A break will on the "seal" will set the code. In your case, hose from tank to canister is compromised.

tbarn Senior Enthusiast

tbarn

Posted
Posted

System is normally open. Pcm closes the vent valve to test.

sefiroxx Enthusiast

sefiroxx

Posted
Posted

Evap is closed when verticals is off. Vapors from fuel tank are passed to the canister.. If pressure builds, the system has an over pressure release valve at the canister.

When the vehicle is running, a valve opens at a certain rpm to allow the stored vapors to be introduced into the intake.

riverbanks Senior Enthusiast

riverbanks

Posted
Posted

Vent valve is open when vehicle is off,purge valve is closed when off,a guy did a test somewhere on here a ways back,purge valve opens on decel,he hooked up a test light to watch,now he didn't test light the vent valve,so during evap leak test,purge opens,vent closes for small leak test,then opens for large leak test?

Coop8202 Enthusiast

Coop8202

Posted
  • Author
Posted

What’s the easiest way to test all of this without pulling the bed?

sefiroxx Enthusiast

sefiroxx

Posted
Posted

Purge opens at certain rpm. Prior to rpm threshold, the system is sealed and there is some pressure which the computer checks with a pressure sensor. If no pressure, the code is set.

If leaking on fill, then there is a hole somewhere (100million + cars don't leak on fill)

sefiroxx Enthusiast

sefiroxx

Posted
Posted

Lots of write ups out there. In general, on earlier cars (20 years +) the valve was opened or closed when engine was warm and in gear and moving.

Later engines, once the engine warms up, the cake is pulse width opened. Small amounts in idle, larger amounts as rpm increases.

The 440 test occurs at one of two points. On some earlier cars, with a pressure sensor and the system purge valve known to be off. In a pulse width system, the system will measure vacuum pressure, shut the valve off and measure pressure again. If the vavuum pressure doesn't change enough, it will set a code.

Coop8202 Enthusiast

Coop8202

Posted
  • Author
Posted

I always shut the truck off when filling it up, but before shutting it off, it’s at idle of course, so around 800-1100 rpm

  • 5 years later...
Coop8202 Enthusiast

Coop8202

Posted
  • Author
Posted

Update: Top of fuel pump rotted out due to design of tank/pump and debris sit down in there. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • PhilB
      No 12v outlets in 2026 gmc Sierra

      By PhilB · Posted

      It is possible to add your own 12v outlet to your truck.  Check out this video:   I verified via GM Upfitters that pin 31 is the same on the 1500 trucks.  The wire is GM part number 84779405.   You can get the GM 12v outlet from Amazon  https://www.amazon.com/Genuine-Accessory-Receptacle-25774623-13549530/dp/B0F1H9YRGF EWAY 12 Volt Power Adapter for GM   https://www.amazon.com/EWAY-Chevrolet-Silverado-Cigarette-Ignition/dp/B0915RRW6Q/ref=sr_1_1?   I just haven't figured out a good place to put the 12v outlet in my truck.   Some people are getting USB-C to 12V adapters  https://www.amazon.com/WYMECT-Cigarette-Lighter-Socket-Adapter/dp/B0F87WNQKB/ref=sr_1_1_sspa? Not sure if they provide the correct amperage that a device like a tire inflator would need.  
    • Core-Lokt
      Wiring Help, Please

      By Core-Lokt · Posted

      Thanks; I looked there a few minutes, and I think I can find something. I really never looked there, as I thought it was stuff like PTO/aftermarket bodies/accessories like snow plows.
    • newdude
      2 speed transfer case optional now?

      By newdude · Posted

      This is a 1/2 ton thing ONLY.  All HDs 2020-2026 have the two speed transfer case, with Autotrac as an option.     1/2 tons 2019-2026, regular 4x4s come with a single speed case (no 4LO!), and trucks with Z71 ordered, or all Trail Boss trucks come with the 2 speed case.  2 speed case is also an option on WT, and is also standard on High Country.  
    • newdude
      Different requirements for oil filters?

      By newdude · Posted

      2013 5.3 still to this day calls for the PF48 filter.  Which as a 15psi bypass pressure.     There is a TSB, 17-NA-157 that talks about the PF-63 and PF-64 filters which have a higher bypass rating of 22psi.    TSB HERE - temp.xml   "Beginning in 2012, the oil pumps began to regulate main gallery feedback instead of pump out pressure. This means that the oil pump now does not begin to regulate until pressure is built up to the main gallery. This change reduces the amount of time it takes to provide oil to the engine bearing and lifters during extreme cold start conditions.  Main gallery feedback oil pump control systems are present on the following engine families which use Spin-on oil filters: Small Gas Engine (SGE), Large Gas Engine (LGE), High Feature (HFV6) Gen2 and Small Block Gen5 gasoline engines. These engines with the main gallery feedback oil pump control systems are factory built with an ACDelco® oil filters"   It also calls out what engines use those filters.  The gen 4 small blocks were not on that list (LMG, LC9, L9H, L92, L94, L20, L96).  Gen 5 small blocks use the higher pressure filter.          That all said...   Your 7045 Napa filter is the PF63 equivalent, with 22psi bypass.  You are already using the higher bypass pressure filter.  You CAN keep using it, you don't technically have to use it though.  
    • Grumpy Bear
      Different requirements for oil filters?

      By Grumpy Bear · Posted

      Do you know WHY the filter relief setting was increased to 22 psig?    When the new system goes into the second stage the pump volume ramps up considerably. It was found that the 15 psi filter bypass setting put the filter in bypass on a warm engine when the second stage was activated. Raising the filter bypass setting forced the filter to do what it designed to do. Filter. Preventing debris from circulating during high load, high rpm operation.    So next question is how did GM find this out? VLOM/lifter failures and a deep dive by Melling Corp.    Last question. Is it required? Look at it like this; a motor may be equipped with a rev limiter. But it only works if the set point in reached. That 22 psig setting only matters if the pressure differential across the filter media exceeds 15 psig during normal warm operation. Second stage kicks in around 3000-3500 rpm.    I can't answer your question because I don't know you and how you use the truck. But I think there is enough information here to let you decide for yourself. 😉

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...