Here is a sweet wagon for some interest to a boring post.
I feel sorry for people who do this. Driving hundreds of miles over days hoping their cars will be ready for emissions testing after disconnecting the battery or do repairs and reset codes or whatevs. I used to be one of them but always suspected the inspectors vague answers of what to do was a bunch of crap and waste of time blindly driving around hoping the car would go through all its checks and failing again when bringing it back to the testing center and trying again.
Long story less long there is something called a Single Drive Cycle. A manufacturer specified idle speeds for specified time and driving at certain MPH for certain amount of times. Its dependent on your car.
I tested my car today and like an idiot forgot to drive it after having the battery die from storage drove right to the testing center after getting a jump start and failing emissions test as the car was not ready. I looked up the drive cycle and 40miles and an hour later went back to the testing center and passed all checks Ok saving myself hours of times and hundreds of miles driving about hoping it was ready.
For example here is a excerpt from a Ford Crown Vic
Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period. From a stop, accelerate to 72 Km/h (45 MPH) at ½ to ¾ throttle. Repeat 3 times. Bring the vehicle to a stop. Idle with transmission in drive (neutral for M/T) for 2 minutes. For M/T, accelerate from 0 to 80 Km/h (0 to 50 MPH), continue to step 11. For A/T, from a stop and in overdrive, moderately accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 64 Km/h (40 MPH) cruising for at least 30 seconds. While at 64 Km/h (40 MPH), activate overdrive and accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 10 five times. From a stop, accelerate to 104 Km/h (65 MPH). Decelerate at closed throttle until 64 Km/h (40 MPH) (no brakes). Repeat this 3 times. Access the On-Board System Readiness (OBDII monitor status) function on the scan tool. Determine whether all noncontinuous monitors have completed. If not, go to step 13.
Really takes the guesswork out of the whole process and gives confidence it is ready for testing. Especially if you don’t have a OBD scan tool to check.
Look up your drive cycle here or find it in a factory workshop manual