Evap Service Bay Test Question

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Corvette Rick
    Member
    • Jul 2020
    • 38

    Evap Service Bay Test Question

    I have a Verus Edge current subscription and im working with a 2012 Corvette that had the battery reset. Unless im missing something i cannot get the evap test to work because of the conditions it requires. To get the proper temp (under 158 degrees) the car has to sit for awhile. Because it sits for awhile it requires you to drive it 20 minutes and 10 miles. Well once you do that your over the temp. You let the car sit to cool down and by the time it does it wants you to drive the miles and 20 minutes again. Its a frustrating endless loop that doesnt allow me to do the test. Am i doing something wrong here or does anyone have any tips ?
  • Joe Rappa
    Snap-on DSD
    • Aug 2007
    • 2050

    #2
    The 156F requirement is just to get the test started. If it's booting you out, there must be something else going out of bounds. What, specifically is happening? That'll help us get you through it.
    Joe
    "You don't build a reputation on what you're going to do"
    Henry Ford

    Comment

    • Corvette Rick
      Member
      • Jul 2020
      • 38

      #3
      Ill try it again when i leave work to put the miles and time on the car for the test. If the engine is under the 158, it will tell me to rev the engine. It will then fail and tell me the reason is it hasnt met the drive time of 19:58 seconds and 10 miles or somewhere in there. My problem is I've done the driving, and then when i exit out to run the test again, it now tells me the car is too hot. When you let the car cool down and go back into it its a repeat of before, the drive time and mileage arent met. It doesnt make any sense. It requires both, but one causes the other to fail in and endless loop. I get the car will run the tests on its own but seems like this test to save time is only a tease. The service manual doesnt say anything regarding this only to follow the tools instructions. I even have a Tech 2 and it doesn't give me the fail reason like the snap on does, so ive stuck with the snap on.

      Comment

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

        #4
        I don't know if you've ever run the test, and it can be tricky. So I'll kinda spell it out here in case that's the trouble.

        With the engine under 160F or so, the EVAP Monitor needs to read incomplete, and the fuel between 15% and 85% command the service bay test.
        It will tell you to rev the engine and give you a specific RPM. Don't worry about holding it at exactly that number. Just keep it at high idle.
        After 10 minutes it tell you the idle conditions have been met. Agree to whatever the scanner says on screen. Drop it in gear and go for a ride.
        After 10 minutes and 10 miles it says the drive portion is complete, and to stop the car. You don't need to stop right there. Those are minimum drive times. Get back to your shop, agree to the scanner again and then shut the key off. In under 30 minutes or so the KOEO portion completes and the scanner gives gives you results.

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

        Comment

        • Corvette Rick
          Member
          • Jul 2020
          • 38

          #5
          Thanks for the quick replies. The problem im having is i never get past the start and idle stage. Ill start the car and idle it, and itll basically fail within 5 seconds and tell me i didnt meet the drive time and distance requirement. I guess what im saying is i cant ever get past that part because it requires 20 minutes driving and 10 miles and the low temp. Its actually impossible to meet both of those conditions at the same time so the test fails from the drive part or wont even let me start it because of the temp. I dont know if its specific to the LS3 corvettes or GM, or if im just totally missing something. But i cant get it to do anything past the first time it tells you to idle it between 1800-2000, it always fails because of the drive time and distance as the reason. Suggestions? I can provide screen shots if that would help.
          Last edited by Corvette Rick; 07-07-2020, 02:43 PM.

          Comment

          • Corvette Rick
            Member
            • Jul 2020
            • 38

            #6
            Screenshot

            This is what happens. I start the test it immediately tly fails. Tells me I need to run the car for 20 minutes and ten miles in the reason. There’s no way to redo the test without exiting out. When you do it resets the timer so you lose any time and mileage gained. Then your temps are too high. So you can see it’s literally impossible to run this test the way it’s programmed. Any thoughts or does it just not work for this car ?
            Attached Files

            Comment

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

              #7
              If it fails immediately the only PID you need to look at is the EVAP Test Abort Reason. The other ones don't mean anything until that part of the test runs.
              Are you certain the Monitor hasn't already set? That's a common problem.
              Your other qualifiers look good, but that's one thing you can't see on this screen.
              Joe
              "You don't build a reputation on what you're going to do"
              Henry Ford

              Comment

              • Corvette Rick
                Member
                • Jul 2020
                • 38

                #8
                Before I ran it I checked and it was the only test marked as not complete in grey from a general scan. When the monitor is already complete the scan tool will tell you and not even let you get into the test. I remember this when I tried it on this car before the battery reset. I don’t think I’ve missed anything but it just doesn’t appear this works for this car. Not sure if there’s anything else we can even try at this point, outside of finding a gm mechanic or corvette tech whose a familiar with this situation. Any other suggestions or Do you have other company resources we can use to find a solution ?

                Comment

                • Crusty
                  Senior Member
                  • Dec 2007
                  • 2450

                  #9
                  Some of the EVAP tests will only allow a test to be done once or twice IN A 17 HOUR TIME PERIOD.
                  That means let it sit for over 17 hours.
                  Also even though the EVAP is the only monitor set as incomplete, SOME of the EVAP self tests may have run already and could be fudging the Service Bay Test.
                  Do a code clear so it has a clean slate to start with for the Service Bay Test. (some service information will tell us this depending on the vehicle).
                  That is a PITA because it then means all the other monitors have to start over again.
                  Are you trying to get the monitors to set or were there codes stored before all this started-?
                  Personally I like to use the Purge & Seal test to see if the system is functional in the first place. Once I know the system is capable of sealing and staying sealed, then it's just a matter of letting the darned thing complete the Key Off Natural Vacuum test on it's own.
                  LOOK at the data for the EVAP while it's doing the Engine Off Natural Vacuum self test. It's boring as hell to sit there looking at pids for 3 or 4 minutes waiting for it to start but if it's quiet, you can hear the Purge and Vent solenoids activate when it does start.
                  You'll know it's starting the EONV test if the scanner keeps communication when you turn the key off.
                  Sometimes the EONV portion will only take2 or 3 minutes before it decides to power down (No Communication will show on the scanner). Sometimes it's taken 45 minutes to complete, and we don't have any way of knowing when or what the ECM was seeing when it decides to shut down.
                  This means saving a movie every minute or so to capture what was going on because once it shuts down, the scanner buffer clears itself as soon as it sees the No Communication screen.
                  It dumps the data buffer so we can't see what the ECM was either happy with, or unhappy with, when it decides to stop the self test and shut down.
                  Dumping the data buffer is a PITA. They COULD set the data to stay there in the scanner and pick up where it left off when the key is turned on again to restore communication, but they've ignored my request for this for years.
                  If the data was till there, and we restored communication, we could simply restore Comm and then save a movie so we could see what was going on, but alas.

                  Comment

                  • Crusty
                    Senior Member
                    • Dec 2007
                    • 2450

                    #10
                    I just looked up one of the three engines available for a 2012 Vette.
                    It states in the Service bay test that the start up coolant must be below 95-F (35C).

                    Comment

                    • Corvette Rick
                      Member
                      • Jul 2020
                      • 38

                      #11
                      This example the coolant was higher then that but I’ve tried it multiple times with it being around 75 or so and it still fails because of the drive test. The scanner says 158 or lower for temp to even start the test. Maybe you are right some of the tests might have started to clear already but I feel like it just doesn’t work for this car based on everything I’ve read and tried. There were no codes it was just a matter of wanting to get the monitors all done instead of the long route for the evap.

                      Comment

                      • tech25
                        Senior Member
                        • Oct 2017
                        • 172

                        #12
                        Have you met all these requirements before attempting a service bay test?

                        engine voltage between 11-18 volts
                        barometric pressure is more than 75 kPa
                        coolant temp is between 39-86F
                        intake air temp between 39-86F
                        difference between coolant and air temp is less than 10.8 F
                        ambient air temp is between 39-86F
                        fuel level is between 15 and 85%

                        the fuel level is a big one. If you meet all of these, all faults cleared.
                        and monitors reset, what happens if you attempt to run the service bay test?

                        Comment

                        • Corvette Rick
                          Member
                          • Jul 2020
                          • 38

                          #13
                          Ive attempted this test many times and it always fails for the same reason, the drive time and distance. I meet all the requirements but when i start the test with the high idle, it immediately fails every time. And says the drive time and distance wasn't met. You cannot do the drive time before the test because then the temp will be too hot. If you do the drive and try to let it sit you still have to back out of the test to restart it, at which point it will tell you you didn't meet that condition again. There's literally no way to satisfy the conditions of this test. I've given up and moved on at this point it simply does not work for this car. The program contradicts itself with its requirements making it literally impossible to run the test.

                          Comment

                          • Nate75
                            Junior Member
                            • Jan 2019
                            • 11

                            #14
                            on the screen shot you posted it only shows the engine OFF test inhibit reason being drive time, need to look at the EVAP test abort reason, not the EVAP engine off test abort or inhibit. as was explained previosly the engine off test is not allowed until the drive requirements are met, you are being failed in the running portion not the engine off part of the test. I have not done the test on your exact vehicle but I think there is something else kicking you out of the test.

                            Comment

                            • Corvette Rick
                              Member
                              • Jul 2020
                              • 38

                              #15
                              In that section it just says lost enable conditions. Even with a Tech 2 it tells me the failed reason is the drive time. I appreciate the responses but this test just doesn't work for this car, as ive tried it every conceivably way meeting all requirements laid out, with it failing the exact same way each time.

                              Comment

                              Working...