What is it:

Most vehicles starting in the 2010 model year were required to add a monitor in the ECU that tracks the number of times certain events occur in some case emissions related in some cases not. These values persist beyond resetting the ECU or reflashing it.  This is in accordance with the ISO standard 15031-5:2011 (here https://www.iso.org/standard/50816.html) as well as California Air Resources Board Title 13 requirements (Found here https://ww3.arb.ca.gov/regact/obdii06/19682clean.pdf).

In most cases it is tracking two things per parameter which can be expressed in a fraction (a numerator and denominator).  Firstly the number of times conditions are correct for a self check for the ecu or various vehicle systems to run (Numerator) , and secondly the number of times the vehicle was operated in those conditions (Denominator)

It will also track some basic information such as the number of key-cycles (times the engine has been started)

These values are essentially a way to sample how the vehicle is running and how various systems are performing.

Steps to Use:

1. Turn your vehicle on and plug your Accessport in.
   
   

2. Go to the "Troubleshooting" menu
   
   
   
   
   

3. Scroll Up and select In-Use Performance Tracking

   
   
   
   
   

4. You can now scroll through the available monitors for your vehicle which may differ.  With one selected a long press of the center button on the Accessport (holding down the button) will open up a description of what the value is.