readiness monitors monitor sensors for emissions reasons. They are compared to data that is collected over a long (40 miles, they say) period of driving under various conditions. Car manufacturers were forced to do this when OBDII was adopted so that people couldn't just clear the codes and get it checked while the code was off.
Anyway, history aside, you have to drive the car at slow speeds, you have to drive it at interstate speeds. For some systems, you have to change your speed a certain amount (not more, not less) over a very specific period of time. Basically, it more complicated than just driving to the store. With the 2.0L that I have, some readiness tests would not pass until I hit interstate speeds for at least 5 minutes. The O2 heater readiness test checks out within a couple of minutes (especially if the car's already hot), the EGR test requires your car to drive under certain conditions to where your EGR valve would open a prescribed amount a prescribed number of times. The evaporative test actually requires you to either leave the car sitting for an hour or so and/or else fill the tank up.
I can tell i'm getting carried away in non-specifics. to make a long explanation shorter, you will not get them all immediately. Some of mine take months to pass. The older the car gets, the harder it is to pass emissions stuff. That's why states will still allow your car to pass emissions tests with 1 or more (depending on car's age) readiness tests still not passing. If you're fed up with going to the shop and getting turned down, then either buy an OBD scanner, have autozone check (they do it for free)
