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Thread: EVAP code analysis and troubleshooting using VCM Scanner

  1. #1
    Potential Tuner
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    Aug 2016
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    Question EVAP code analysis and troubleshooting using VCM Scanner

    Hello all,

    2010 Chevrolet Cobalt SS here, not sure if my question should go here r in the L4 forum, but here goes...

    I have p0497 engine code for EVAP low purge flow. I've been tuning my car for a while with the help of a lot of great tuners on this site and cobalt ss, car runs great. Using MVPI plug-into-laptop method. I'm looking to log the things GM says to do while diagnosing this DTC, most notably the steps like:

    "Seal EVAP system using purge/seal function" or if this special feature isn't available, I'd like to know how to do this step "Observe FTP (fuel tank pressure) sensor with a scan tool, should be more than two volts". I can upload my tune file and my scanner configs, perhaps I can add the scanner and/or graph for that sensor so I can log this?

    I can fix 100% of my car's issues on my own, but this EVAP stuff is kicking my butt. Need to pass inspection. I have stock downpipes but cats removed because they clogged up on me so I smashed them out. A leftover item from a Halloween party, I have a fog machine that I used to fog out all my EVAP lines, they're clear and leak-free. I blew them out with low pressure air, >5PSI, in case any carbon was in the lines.

    At a loss for how to fix this, and how to use HPTuner software to assist me with finding the root cause. Any assistance would be appreciated, thanks!

  2. #2
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    Aug 2016
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    I forgot I made this post, checked back to see no replies lol... I was able to turn off codes pertaining to the EVAP system, so that system is always 'Incomplete' but all other monitored systems are ready and working so I legally passed inspection. If others have the same issue, just turn off codes pertaining to that system and you won't see the MIL but you will set that specific OBD2 monitor to incomplete. No way to set it to something else, not on these cars..

    and I also found this sticky at the top of the VCM Scanner section! No wonder I didn't get any replies, the answer was right in front of me https://forum.hptuners.com/showthrea...nd-VCM-Scanner

  3. #3
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    Jul 2019
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    Quote Originally Posted by Turbo Johnny View Post
    I forgot I made this post, checked back to see no replies lol... I was able to turn off codes pertaining to the EVAP system, so that system is always 'Incomplete' but all other monitored systems are ready and working so I legally passed inspection. If others have the same issue, just turn off codes pertaining to that system and you won't see the MIL but you will set that specific OBD2 monitor to incomplete. No way to set it to something else, not on these cars..

    and I also found this sticky at the top of the VCM Scanner section! No wonder I didn't get any replies, the answer was right in front of me https://forum.hptuners.com/showthrea...this link</a>.
    That's great you can find the solution. Sometimes, we can find the answer by another person question. Anyways, thanks for sharing this.