When CEL/DTC codes are cleared…they are gone. Any associated I/M monitors go into “Not Ready” mode.
They will display that until the vehicle has gone through the proper drive cycles for each monitor. They will then show either “Ready” or throw a code.
If you went to an auction and scanned a car that had I/M monitors in “not ready” status…they were reset very recently. Either gamble on an easy fix…or walk.
I have the CHEAPEST scanner I’ve seen. Actron lowest level reader from Advance Auto…it has the ability to check I/M monitors.
What models are you using?