evap test wont run

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  • wayno
    Senior Member
    • Jul 2011
    • 250

    evap test wont run

    Tried to run evap test on 1999 chevy tahoe and scan tool came up error and said evap machine wont run 1gnek13rsj493587.Tried several time and kept coming up with error message.
  • Chevytruckman1234
    Senior Member
    • Mar 2008
    • 108

    #2
    Did you meet all the criteria to run the monitor ie: no DTCs, fuel level between 1/4 and 3/4?

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    • Bob's Garage
      Senior Member
      • Nov 2007
      • 3257

      #3
      What version of software?

      Originally posted by wayno
      Tried to run evap test on 1999 chevy tahoe and scan tool came up error and said evap machine wont run 1gnek13rsj493587.Tried several time and kept coming up with error message.
      Hi Wayne,

      Which Evap test?

      Purge and Seal or Evap Service Bay Test?

      Many times the ESBT will be denied due to codes, engine temp, tank fill, unstable RPM, unstable fuel level etc..

      Could you post a screenshot? Use the S button and capture the image.

      It sounds like a scanner issue, due to the "Machine" terminology though.

      Do you know what version of software you using? That may be helpful.

      Thanks, Bob

      Comment

      • Crusty
        Senior Member
        • Dec 2007
        • 2450

        #4
        Originally posted by wayno
        Tried to run evap test on 1999 chevy tahoe and scan tool came up error and said evap machine wont run 1gnek13rsj493587.Tried several time and kept coming up with error message.
        First of all, Chevytruckman is correct. You need to go into either the engine data 1 group or the sensors group and check that the ECT, IAT and FTL% (FTL% won't be there-!!! but you should be able to either check the dash guage or gues by looking at the FTL-volts which should be somewhere between 2.1-volts and about 0.7-volts)
        The spec for the fuel level PERCENT-!!! (is SnapOn listening-???) is usually BETWEEN 15% and 85%. The occasional vehicle specs 20% and 88% so just make sure you have a little more than a 1/2 tank.
        Take a look at the criteria to enable the system to self test in a bunch of the P044x codes....P0440, P0442 and especially P0446 in your information database such as AllData.....

        There should be about 4 different evap tests you can run as Bob says.
        Purge solonoid ON/OFF
        Vent solonoid ON/OFF
        Purge & Seal
        Then finally the Evap-Service-Bay-Test, which will raise the ECT temperature allowed to run the test, which is higher than the 38-F to 86-F window that the code criteria requires (aproximate guess here but you get the idea...look at the code charts for details).
        This last one, the EVAP Service Bay Test, is not in every GM vehicle's PCM, so I don't use it very often. Sometimes it's there but SnapOn doesn't show it, sometimes it's not in the PCM and SnapOn does show it.

        The first three tests should be active regardless of the ECT, IAT and FTL% but the vehicle's self tests and the EVAP SBT do require the enabling criteria to be met.
        When you are looking at the fuel-tank-pressure pid, it will show in mmHG for vacuum on your scanner. To convert to INCHES OF WATER COLUMN, as the code charts direct you to look at, use the mmHG value and either multiply or divide by 1.86 and 0.5353, (eg; -14.5 mmHG = 7.76 inH2O)

        HTH

        Comment

        • wayno
          Senior Member
          • Jul 2011
          • 250

          #5
          Thanks for replies i posted in wrong forum.Problem with scan tool it self wont let me run at all keeps coming up with error code.

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