Check engine light is on

Discussion in 'Member Introductions' started by Jeremx, Jan 18, 2014.

  1. Jeremx

    Jeremx New Member

    Hi new to this but my buddy check the code on my 06 avalanche 5.3l and the code stated that my purge valve was either shorted or I replaced it still on any ideas please help and I was told to put a bulb In the connector and turn on the engine and should light up but it did not
  2. silverad01

    silverad01 New Member

    code number?
  3. Jeremx

    Jeremx New Member

    I will have to find out sry

    - - - Updated - - -

    Code is po446
  4. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    A replacement valve didnt solve the problem, and testing for power at the connector showed no voltage since it didnt come on.

    I think theres an actual voltage test with a meter where you should get a specific voltage reading. The reading might not be enough to light up a basic bulb.
    If the voltage reading doesnt pass then you need to start tracing and reading the harness for breaks.
    Possibly do a continuity test on the harness to test for wire breaks.
    If that test shows no breaks then you need to test the source to find if its even sending a signal.
  5. Jeremx

    Jeremx New Member

    I went got a scan tool command the vent valve to open and close did I have voltage I preformed a test found not holding pressure meaning I have a crack in a line I'm told and need a smoke test done now hate trucks and cars at times lol thanks for the help and hope I can get someone to find the leak I guess dealers
  6. the phantom

    the phantom Epic Member 5+ Years ROTM Winner 1000 Posts

    Welcome to the club!!! Yeah thats the pain with emissions testing. It basically keeps the fumes from escaping into the atmosphere and gets filtered through a carbon filter. If pressure is not building it senses theres a "leak" somewhere. The vent selonoid opens when a certain amount of pressure is sensed in the tank. Generally this problem will not effect how the engine runs. But will not pass some places for inspection like here in NY. I wouldnt be concerned about driving it until time and money allows for it to be fixed. A smoke machine is the fastest way to find the leak. some can just be a crack in a vent line that cannot be seen (most likely). Make sure your o-ring on your fuel cap is not all cracked, theyre common for dry rotting and allowing pressure leak causing engine light on.

    PS. Also if your in a place that salts the roads. Ive seen the secondary(overflow if you will)hose where your filler tube is crack or rot out. This would also not allow pressure buildup and turn the check engine light.
    Just some ideas good luck.
  7. Enkeiavalanche

    Enkeiavalanche Loving the Outdoors Staff Member 5+ Years ROTM Winner 5000 Posts

    Sounds like the Ol' Evap.. Lots are getting that code.
  8. Jeremx

    Jeremx New Member

    Wow thanks for the help and ya it won't pass etest here and we get a lot of salt and I will check the hoses and cap and go from there and I was told if I left this problem the truck would not be good on fuel is that true
  9. the phantom

    the phantom Epic Member 5+ Years ROTM Winner 1000 Posts

    Its going to depend on the exact cause. If its just an evap code from an opening in the system(cracked vent line ect) I dont think this would effect your fuel milage IMO.
  10. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    make your own smoke machine with a 2 liter bottle and a cigarette. I did the best I could at drawing it with no access to good software. I have made them multiple times. Just go buy a hose barb that will fit the ID of the hose you need to test. Take a cap off od a 2 liter bottle and drill a hole in it to fit the barbed part of the hose barb. Slide the hose barb into the bottle cap from the inside, leaving the threaded end facing inside the bottle. The ID of the threaded part should hold a cigarette filter pretty well. Put a small hole in the bottle. Light a cigarette, insert it into the threaded section of the hose barb in the cap. Screw the cap onto the 2 liter, put the hose barb on the hose you need to test. Now cover the hole you put in the bottle and squeeze. It will blow smoke out, take your finger off of the hole and let the bottle fill with air again. finger over the hole, squeeze, repeat. It could take a few cigarettes to get enough smoke especially if you have an empty fuel tank. I have been able to find bad tank seals at the fuel sending unit, bad gas caps, and holes in lines like this. If you want it to work faster you can put a tire valve stem in the hole in the bottle. Then hook up some sort of air pump to it. (I use a air compressor, but a 12volt tire inflater works very well because most of them have an end on them that you can lock onto the valve stem) I found this to be much cheaper than going to the dealer for their smoke machine, unless you live in NY where cigarettes are $15 a pack. :lol:the most I have used at one time where 2 packs

    Last edited: Jan 20, 2014

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