it's kinda different for different vehicles.I can disconnect my battery on my 2000 F150,that resets to factory settings(8 monitors not ready) then re-connect the battery,drive it 20 miles round trip or less, stop and go,when I get back home,all 8 monitors are set to ready,BUT I have talked to folks that drive up to 600-800 miles and still monitors not ready.(they have problems)! if you have no problems,then 50-150(couple of days) should do it,around town,stop and go,heat on,heat off,A/C on,A/C off,interstate driving. or you could try below method....
First make sure that the
fuel level is between 15% and 85%. If the tank is all the way full or close to
empty, the evaporative emissions monitor won't run. Let the truck cool off
completely (overnight is best). Start the truck in the morning and let idle for
15 minutes to warm up and run the evaporative emissions test. After idling for
15 minutes, drive to the nearest interstate highway. You will need 10-15
minutes of steady state cruising at 55-65 mph to run the oxygen sensor test.
Cruise control works well for this. Do not exceed 65 mph or drop below 55 mph
if at all possible during this portion of the drive cycle. After 15 minutes of
highway driving, pull off on the shoulder of the road and let the truck idle IN
DRIVE (neutral for manual trans only) with your foot on the brake for 2
minutes. This will trigger the catalytic converter test. After the 2 minutes of
idling in drive, all the tests should be complete. If this still does not work,
it is possible that your replacement battery is weak. Dodge and Chrysler
products are especially sensitive to losing computer memory with a weak (or
undersize, or cheap) battery. If the voltage drops below 10 volts when the
starter is engaged, the memory in the computer will "dump" and you
will have to start the drive cycle all over again. If you suspect that this is
the case, do the drive cycle procedure, drive to the inspection station, and
LEAVE THE ENGINE RUNNING. This will prevent computer memory loss during
start-up
