What makes a monitor appear as "Not Ready "?
Once any non-continuous monitor runs completely, at least one time, it will be displayed as "Ready",
and will continue to be displayed as "Ready" unless:
In either case, non-continuous monitors change back to "Not Ready". They stay that way unless the
vehicle is driven until the monitors can run again
Someone erases DTCs with a scan tool
Or, power to the vehicle computer is interrupted for any reason. This commonly happens when
the battery goes dead or is disconnected.