Hard time getting Emissions monitors to set? Here's what I found.

[repairman54]

Could not get monitors to test and go green on my '11 5.3 to pass NJ inspection. No P codes or any codes for that matter. No amount of drive cycles would work. My PC based scan tool, Autoenginuity, has 2 MAP sensor tests in it. Found one test would fail erratically. I hate throwing the parts dart but that was the problem. A quick test for that issue is the real time MPG on the dash should go to 99 mpg when coasting downhill from say 55 mph. Mine would only go to maybe 70 mpg or less without touching the gas pedal and bounce up / down. New sensor and back to reading it's normal 99 mpg when coasting. Bonus was highway mileage going from 16-17 mpg back to it's normal 19 mpg with a Range AFM disabler keeping it in V8 mode. Hope this helps someone.

 

[89Suburban]

Could not get monitors to test and go green on my '11 5.3 to pass NJ inspection. No P codes or any codes for that matter. No amount of drive cycles would work. My PC based scan tool, Autoenginuity, has 2 MAP sensor tests in it. Found one test would fail erratically. I hate throwing the parts dart but that was the problem. A quick test for that issue is the real time MPG on the dash should go to 99 mpg when coasting downhill from say 55 mph. Mine would only go to maybe 70 mpg or less without touching the gas pedal and bounce up / down. New sensor and back to reading it's normal 99 mpg when coasting. Bonus was highway mileage going from 16-17 mpg back to it's normal 19 mpg with a Range AFM disabler keeping it in V8 mode. Hope this helps someone.

Thanks for the info. You still have to remove the range device and drive some cycles to pass emissions correct? I go through this crap every year over here in SE PA. There has been some in depth discussions on this subject on this forum. Specifically in this thread. Curious of your thoughts.

Range AFM Delete and Emissions

I realized I had hijacked a thread on Tahoe/Yukon longevity with a complete side track of how the Range device affects emissions testing readiness when it is pulled out before you go in for an emissions test, so I thought I would move things over here (if anyone really cares. ;)). There have...

www.tahoeyukonforum.com

 

[repairman54]

Thanks for the info. You still have to remove the range device and drive some cycles to pass emissions correct? I go through this crap every year over here in SE PA. There has been some in depth discussions on this subject on this forum. Specifically in this thread. Curious of your thoughts.

Range AFM Delete and Emissions

I realized I had hijacked a thread on Tahoe/Yukon longevity with a complete side track of how the Range device affects emissions testing readiness when it is pulled out before you go in for an emissions test, so I thought I would move things over here (if anyone really cares. ;)). There have...

www.tahoeyukonforum.com

I pulled the Range out to make sure monitors reset. I have not verified it but I think some of the monitors need to run in the V4 mode of constant cruise to run the EVAP test.