Here is a blurb on how to go through the drive cycle for obdll emissions testing:
Vehicle models affected: 1998 and newer.
Some dealers’ vehicles have not been able to complete the new Drive Clean test because the on-board computers were “not ready.” Here’s a short primer on what you need to know to be test-ready.
Drive Clean’s new test reads information on a car’s built-in computer. A “not ready” test result means the computer’s monitors didn’t have the necessary information to complete the test. The fastest way to replace missing information is to take the car through a drive cycle. Here’s a generic drive cycle:
Step 1: Make sure the vehicle has been parked for eight hours without a start.
Step 2: Start the engine and let it idle in Drive for two-and-a-half minutes with the Air Conditioning (A/C) and rear defroster on.
Step 3: Turn the A/C and rear defroster off. Drive the vehicle for 10 minutes at highway speeds.
Step 4: Drive the vehicle for 20 minutes in stop-and-go traffic.
Step 5: Your drive cycle is complete. You can now go in for your test.
Gas tank should be ¼ to ¾ full. Driver should avoid rapid acceleration.
The generic drive cycle works for most vehicles. However, go to aftermarket sources or the vehicle manufacturer for drive cycles for specific vehicles.
Why wasn’t the vehicle ready to take the test?
On the lot for a long time with a dead or disconnected battery.
Recent engine repairs or maintenance that may have stopped battery power.
Weak battery that can barely start the engine and shows voltage dropping during cranking.
Computer codes have been cleared or reset.
You can also do a quick check for readiness before taking the test. Plug a portable scan tool into the vehicle’s diagnostic link connector to see that monitors are ready. If they are not, then the car needs a drive cycle.