New to me MODIS?

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  • Sharkz
    Junior Member
    • Mar 2013
    • 4

    New to me MODIS?

    Hello everyone,

    New to the forum and the MODIS. I have been reading and trying to learn the operating system of my MODIS. Watched the DVD and plugging along slowly taking the time to try and learn everything.

    What I'm most interested in at this time is how to perform a EVAP service Bay test on a 05 Colorado. I believe my MODIS has the 10.2 software? I apologize I don't have it right in front of me as its at the shop.

    Thanks for any insight you can offer.
  • Joe Rappa
    Snap-on DSD
    • Aug 2007
    • 2050

    #2
    From the Main Menu
    Go to Functional Tests
    Choose EVAP Service Bay Test, if it is present.
    Follow the directions on screen.

    Because it is an '05 it probably has to be driven and then shut off for 30 minutes or so, for the Small leak, and Very Small Leak portion of the test.

    Joe
    "You don't build a reputation on what you're going to do"
    Henry Ford

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    • Sharkz
      Junior Member
      • Mar 2013
      • 4

      #3
      Thanks for the fast reply Joe! As luck would have it the truck has a full tank of gas From all the reading I'm guessing the tank should be around 1/2 tank for this test to be accurate?

      Comment

      • Joe Rappa
        Snap-on DSD
        • Aug 2007
        • 2050

        #4
        Originally posted by Sharkz
        Thanks for the fast reply Joe! As luck would have it the truck has a full tank of gas From all the reading I'm guessing the tank should be around 1/2 tank for this test to be accurate?
        Service info says 15% - 85%, but in my experience anything over 75% can prevent it from running. It is also best to run it from a cold start. I've used a water hose to cool them off if needed.
        "You don't build a reputation on what you're going to do"
        Henry Ford

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        • Sharkz
          Junior Member
          • Mar 2013
          • 4

          #5
          Joe thank you for the quick replies. I'll be running the test tomorrow. Thanks for the help.

          Comment

          • Crusty
            Senior Member
            • Dec 2007
            • 2450

            #6
            Originally posted by Sharkz
            Thanks for the fast reply Joe! As luck would have it the truck has a full tank of gas From all the reading I'm guessing the tank should be around 1/2 tank for this test to be accurate?
            Hi and welcome to the forums.

            Lots of knowledgeable people on here and nowhere near as rude as iATN. Here a question is asked to get an answer, not ridicule-!!!

            Take a look at any GM vehicle in your information database. Look at the codes for P0440, P0442, P0456.....take note of the "conditions for running the test".
            Observe the preset conditions that must be met before the ECM/PCM will even TRY to evaluate the systems. They;re all pretty standard with some small variations between vehicles.
            One that comes to mind is the minimum amount of fuel allowed so there is a vapour space but not all vapour. MOST state that the minimum amount of fuel is greater than 15% by volume (eg; SOME say 12.5%).
            Another is the maximum amount of fuel allowed....less than 85% (eg; SOME say less than 87%)
            ECT & IAT must both be above 38-F and below 85-F and within a certain number of degrees of each other.

            There are 2 basic systems.....one checks itself and pulls the vacuum down and seals the system and monitors the speed of vacuum decay. The newer one starting around 2005, 2006 and newer is the EONV system...(Engine-Off-Natural-Vacuum), which will pull the vacuum down, monitor the decay and then after shut down keep the PCM awake while it closes the system and monitors the FTP increase above atmospheric and then several minutes later (as much as 45 minutes later) it continues to watch that pressure cool down and pull a vacuum.

            Try the Purge-&-Seal function......see how THAT operates because that is what the PCM is going to do on it's own.

            Ask any questions you want. Most of the people here are good guys (gals)

            Read the other forum groups. The scanner portion of your Modis will function very similarly to the other SnapOn tools in the basic functionality (with small variances)
            Take a look at the EVAP form for example. More detail on the EVAP systems.

            Comment

            • Sharkz
              Junior Member
              • Mar 2013
              • 4

              #7
              Crusty thank you for the detailed analyst. Not sure I understood it all but I'll try and process everything in the morning. Thanks...

              Comment

              • Crusty
                Senior Member
                • Dec 2007
                • 2450

                #8
                Most of the time the EVAP monitor has to have the ECT & IAT close to each other. For this to happen the vehicle usually has to be left alone for several hours.

                The Fuel tank level has to be not all vapour and not all liquid.

                It checks the engine run time and won't start the instant you fire it up

                On some vehicles it looks for a Vehicle speed to be above (and below) a certain speed

                On some it wants to see 7% throttle opening

                And some others but those are the basic prerequisites

                Read up on all the codes above P0430 and below P0470

                P0446 is another one that has many details.

                It'll make sense once you can read them. Don't cram all the details in each one. Just take note of the descriptions and the conditions for running the code. You'll soon see the patterns and the similarities.
                Look at a few trucks and look at a few cars. If you've got one handy and it's cold, plug the scanner in, get the EVAP data up on screen, put the A/C on defrost moderate temperature and fan setting, Take note of the ECT & the IAT and the Fuel Tank Level. Then just start it up and watch the Vent solenoid, the Purge solenoid and the Fuel Tank Pressure. Let it idle for about 1 to 2 minutes then drive away slowly, gradually get up to 40 MPH.
                Save a movie at 4 minutes and 8 minutes and 12 minutes then playback the movies in ShopStream-Connect (SSC)

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