Not ready means the ECU isn't accepting the reading based on the recent drive cycles. If the sensor is not ready, it will not throw a code (because the ECU doesn't trust it). That's the reason the new test checks for a valid ready state and stored codes. If it didn't check for ready state, you could just reset the ECU in the parking lot and it wouldn't have any codes stored.

You can absolutely get a conditional pass because of sensors not ready. The condition is that when you come back for the re-test (minimum of 24 hours after the original test) you have the same number, or less, sensors not ready as the original test.

Like I said above, my wife's Camry had three sensors not ready (at the time she was driving < 5km each way to work, so the car was never getting fully warmed up). After it failed on the sensors not ready I took it for a couple WOT pulls on the 407, and came home. Probably drove about 20km's total once it was warmed up. Took it back the next day and it passed with every sensor ready, and no codes stored.

The drive clean website used to have a full list of a good drive cycle that should get everything ready, but I can't find it anymore on their new site.

https://www.ontario.ca/driving-and-r...-clean-re-test

The test centers also had brochures about a year and a half ago, not sure if they still do or not.