Let's have a look at this 2004 Chevy Truck that was dropped off at SMA from another shop that was having trouble diagnosing the classic P0446 "EVAP Vent Performance." Honestly folks the GM Purge / Vent type systems are the easiest systems to diagnose. Take the time to look at the videos below put out by Mike Becker from Wells Vehicle Electronics and educate yourself on these before throwing parts at it. Some of the best vids on the web IMO. -Enjoy!
Wells EVAP Training Videos: https://www.youtube.com/playlist?list=PLq_Q0mT6-rccmY5Ai-CtVf9Xjgk9CpdeO
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50 thoughts on “Chevy / gmc – p0446 evap system vent performance problem”
  1. Avataaar/Circle Created with python_avatars Donnie Cosby says:

    How did you reach the pressure sensor on top of the tank? I've been stuck for days up in here..

  2. Avataaar/Circle Created with python_avatars East Coast Frank says:

    Love your videos!

  3. Avataaar/Circle Created with python_avatars moonrider19681 says:

    I can tell Eric is not a Chevy guy.

  4. Avataaar/Circle Created with python_avatars Kaibil66 says:

    great video

  5. Avataaar/Circle Created with python_avatars My Life Thai says:

    You and 1A Auto parts are my two favorite mechanics videos to watch on youtube!

  6. Avataaar/Circle Created with python_avatars gregory ariel says:

    Lol when you said stupid chevys and stupid keys. I have the same issue on my 2005
    and it drives me nuts. But id still never drive a Ford!

  7. Avataaar/Circle Created with python_avatars Ricardo Castaneda says:

    Why not lift the bed and then have plenty of room to access the gas tank? Takes about 15 min to do.. Loosen 4 bolts 3/4 on the passenger side of bed and remove the other 4 bolts on the drivers side. Unplug left rear harness lights and jack up the bed on the drivers side, using short 2×4 or 4×4 and hold with jack stands… Can also remove fuel pump easily if need to…

  8. Avataaar/Circle Created with python_avatars Rocky Nix says:

    Hay fella ….. Which is best the OTC or the Autel …. Like the Way you multitask on the OTC ….. Thinking about buying the ms906 bt . What would you recommend .

  9. Avataaar/Circle Created with python_avatars Rocky Nix says:

    I heard something fella …

  10. Avataaar/Circle Created with python_avatars Two brothers pythons says:

    Any symptoms?

  11. Avataaar/Circle Created with python_avatars Two brothers pythons says:

    What was the issue?????

  12. Avataaar/Circle Created with python_avatars Two brothers pythons says:

    Will this cause stallings

  13. Avataaar/Circle Created with python_avatars Two brothers pythons says:

    Will this cause a misfire??

  14. Avataaar/Circle Created with python_avatars Lionel Vasquez says:

    What type of lube did you use for the O-ring on the Fuel Pressure Sensor?

  15. Avataaar/Circle Created with python_avatars sam bitar says:

    Eric, you are so technical in your approach and knowledgeable especially when you indicated that the system will check on leaks after the facts and this genius," lucky you perfect businessman".

  16. Avataaar/Circle Created with python_avatars ROCK777 Garage says:

    J

  17. Avataaar/Circle Created with python_avatars *D C* says:

    Love your videos man ๐Ÿ‘ you have the best views and explanations on YouTube ๐Ÿ‘ keep up the good work ๐Ÿ˜€

  18. Avataaar/Circle Created with python_avatars Ali says:

    Thanks

  19. Avataaar/Circle Created with python_avatars CasperE. says:

    Nice video, and nice hat!

  20. Avataaar/Circle Created with python_avatars The_g35life says:

    You just gotta jiggle them keys partner๐Ÿ˜‚

  21. Avataaar/Circle Created with python_avatars Averys Life says:

    Would fuel pressure sensor cause the truck to idle really rough? Got the same code but canisters been replaced and wiring looks fine. Keeps saying evaporate harness

  22. Avataaar/Circle Created with python_avatars Dustin Schings says:

    These scanner tablet tools you have probably cost a LOT of money. Why do they always use ancient, cheap, and SLOOOOOW tablets when they produce them?? Awesome video!!

  23. Avataaar/Circle Created with python_avatars Casey Cleland says:

    Hey Eric I have a 97 Chevy and before I bought it the owner before me so that they replace the fuel pump and now the gauge isn't working and I got codes coming up saying about the EVAP sensor and a charcoal canister performance issues and I replace the purge solenoid and I'm still having issues what can be the cause for the reason for the new fuel pump not reading on the gauge properly and fluctuating randomly would that have any negative effect on the EVAP system to

  24. Avataaar/Circle Created with python_avatars Spikewess says:

    Save me a lot of money!
    Check engine light was on; Code p0446. All I did was hit my VSV with a screw driver and got the valve to kick in or out! Thank you very much. (1997 Toyota camry v6)

  25. Avataaar/Circle Created with python_avatars Hi Reeler says:

    thanks for info good video

  26. Avataaar/Circle Created with python_avatars Julio Rubio says:

    Hey s.r. I have a chevy malibu hybrid 09 whit h the po446 but we're is the fuel tank pressure sensor located .can pls let me know

  27. Avataaar/Circle Created with python_avatars MotoSexual says:

    awesome content, but that UI on that scanner would PISS ME OFF.

  28. Avataaar/Circle Created with python_avatars Timothy A says:

    Well most comment's are 3yrs old. So I doubt anyone in what's left of my lifetime will read this. ( I'm old lol ) ( bought used car in new place) ( picked shop closest to me so I could walk home)
    I only can hope that the shop I have chosen has a mechanic that has your skills. My car is 20yrs old runs great, but money light has been on for past 4 months and inspection expires apr 1 2021. Willing to put some money in her as long as it fixes it and I can continue to get to work.

  29. Avataaar/Circle Created with python_avatars James Fainter says:

    Does anyone happen to know what the price could be to fix this? Great video thank you.

  30. Avataaar/Circle Created with python_avatars Matthew Miller says:

    you may have just solved my problem… i keep getting a PO446, vent valve and purge valve are both working properly, i would've never thought about a tank pressure sensor (and my scan tool doesn't give me that data) but i guess ill be changing it when i fix the sending unit. ๐Ÿ‘๐Ÿผ

  31. Avataaar/Circle Created with python_avatars A says:

    Thanks for all you do ! It means a lot.

  32. Avataaar/Circle Created with python_avatars Redd Smith says:

    Chevys are the BEST BEAST TO HAVE

  33. Avataaar/Circle Created with python_avatars Benjamin Fuller says:

    On my Silverado I'm thinking about making a open and closing hatch for the fuel pump and stuff

  34. Avataaar/Circle Created with python_avatars Gary Walker says:

    Great video. Really good diagnostic process

  35. Avataaar/Circle Created with python_avatars Ricardo Andrade says:

    GOOD game, and Job!

  36. Avataaar/Circle Created with python_avatars Daniel Arney says:

    As long as it has a radio, cup holders, back up cameras, heated seats, etc, they will keep selling more and more electrical nightmare junk. Should be easier to fix, could be easier to fix, maybe it shouldn't need to be fixed.
    Epa should not be used as a pry bar in our broke asses. Epa should not be able to manipulate us to buy something that is not needed without a vote.
    Can't wait to see how they justify their existence in auto industry when everything is electric in 2035. Wait, did majority vote for that? Sure industry and tax man are basterdizing their designs so no one can touch them as we lube up the bung holes in anticipation. Sick of it
    All.

  37. Avataaar/Circle Created with python_avatars craig jones says:

    I see why some guys just put the parts in. It takes a lot of money in scan tools to replace the simplest things. Great video.

  38. Avataaar/Circle Created with python_avatars Martin Kucic says:

    What?

  39. Avataaar/Circle Created with python_avatars William Mason says:

    I learn a lot from you

  40. Avataaar/Circle Created with python_avatars Donald Rackley says:

    Great video Mr owe .as usual enjoyed every minute of it

  41. Avataaar/Circle Created with python_avatars 1337penguinman says:

    Trying to get a GM key to turn that doesn't want to. Anyone who has ever worked on cars at all knows that frustration.

  42. Avataaar/Circle Created with python_avatars j k says:

    Hi Eric Great video!!! I am chasing a evap tank pressure code > my mechanic Bud said he would read the codes and system for 40.00.
    He said I was right the tank pressure sensor was the problem was 0 volts reading…so is that lack of voltage from PCM or broken wire or bad Tank pressure switch… Where does the tank sensor get it's 5 volts from so i can trace it. I know the evpa canister gets a ground feed for PC1 pin 17 2005 envoy . Is the power source from the PCM I need a diagram'

  43. Avataaar/Circle Created with python_avatars Josh Brobud says:

    Hey let me bring my truck in to be fixed with an empty gas tank and a dead battery…..

  44. Avataaar/Circle Created with python_avatars Kalebess Eskew says:

    Just replaced original battery on my 02 with 354k miles

  45. Avataaar/Circle Created with python_avatars Dg 27 says:

    Great method

  46. Avataaar/Circle Created with python_avatars Jo10Mo says:

    Hey I had a P0446 code on my 04 Chevy Tahoe and they have replaced the Evap canister a few times and still get the money light comes back what else could be causing it

  47. Avataaar/Circle Created with python_avatars Tyler Bishop says:

    What exactly are you using to diagnose the vehicle? I love it and it seems like a great investment!

  48. Avataaar/Circle Created with python_avatars Jeff Held says:

    I commented on your other EVAP vid – P0455. I chased that money light rabbit to no avail. Saw this vid and decided to check the fuel tank pressure sensor. I could check & verify voltage but that was it. Replacing the vapor vent solenoid and purge valve didnโ€™t correct the fault so I ended up at the fuel tank pressure sensor. I did not raise the bed or drop the tank. Sure as heck the sensor tip broke off. Got the soft sensor seal out and was able to wiggle the new sensor in. Did the specific GM โ€œdrive cycleโ€ a couple of times and the permanent P0455 was gone. Much appreciated!!

  49. Avataaar/Circle Created with python_avatars All Out Gaming says:

    Get to the point instead of taking 30 mins to look at ur slow ass tablet

  50. Avataaar/Circle Created with python_avatars GoTech says:

    Hey Eric, thanks for the shout out man!!! Great video as always!!! ~Mike

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