It is not just miles, but a drive cycle.
This will give you some idea of what is needed
How to Perform a Basic Drive Cycle
What Is the Purpose of a Drive Cycle?
When a vehicle has an emissions system problem, it almost always
triggers a Check Engine or Service Engine Soon Light. This signals that
an emission system problem and fault code has been recorded in the
powertrain control module (PCM). The problem indicated by the fault code
must now be accurately diagnosed and repaired.
After the proper repair has been completed and the fault code cleared,
the PCM will run a series of self-tests to determine whether or not the
repair actually corrected the problem and if the various emissions
systems are running properly. If they are, they can now properly
minimize the emissions released into the atmosphere from the vehicle's
This process was designed to prevent a vehicle from slipping through an
emissions test with a known problem. Until 1996, a common tactic was to
turn off the Check Engine Light by clearing the code just before an
emissions test, without performing the proper repair. The Drive Cycle
and Emissions Readiness Monitors have, for the most part, stopped this
How to Perform a Basic Drive Cycle
Step One: How to Prepare Your Vehicle
Have the fuel tank between 30 and 70 percent full. Some systems,
especially the EVAP system, need to have a specific level of fuel in
order for the tests to be trusted. If the fuel tank is near empty or
completely full, many of the basic tests will not run at all.
The vehicle must also have a good alternator and a strong battery. If
you have to occasionally jump-start your vehicle, all of the memory from
the powertrain control module (PCM) is erased, which includes the data
that accurately tracks the results from various stages of the Drive
Cycle. Also, if the battery is weak or undercharged, some of the most
important tests will never run.
The vehicle must sit overnight, or for at least eight hours, in an
environment that is less than 90° F. The engine temperature needs to
match the air temperature in order to establish an accurate baseline for
the testing. If the outside temperature is over 90° F, the fuel is too
volatile and the EVAP system won't even try to run its tests, though
some of the other emissions systems may run their tests.
The keys must be out of the ignition and all of the doors must be closed
while the vehicle sits over night because many of the onboard computers
"boot up" when the keys are in the ignition. Also, many of the onboard
computers still run until all of the doors are closed after the vehicle
is shut off and the keys are removed.
Step Two: The Cold Start
Start the vehicle and let it idle for two to three minutes in Park or
Neutral. While it is idling, turn on the head lights, heater/defroster,
and rear defroster for a three to five minute warm-up phase. Let the
idle speed settle down to near the normal speed.
Next, put the vehicle in gear and drive through city streets at about 25
mph. Go up to about 35 to 40 mph a few times before slowing down to
stop. Don't roll through the stop; be sure the car is really stopped,
just like you learned in driving school. Accelerate from each stop in a
normal fashion—not overly conservative, but not like you are competing
in a drag race either.
Step Three: A Short Freeway Trip
After the vehicle has been cold started and driven for a few miles on
city streets, the next step is to take it on a short freeway trip.
Enter the freeway on-ramp and allow enough room with respect to other
vehicles so that you can do a 1/2 to 3/4 throttle acceleration up to
When you have accelerated up to around 60 mph and have safely merged
into the flow of traffic, stay in the slow lane and maintain a steady
speed of 55 to 60 mph for a minimum of five miles. Please use the cruise
control to help you maintain speed.
Find a nice, long off ramp to exit from the freeway. As you exit, take
your foot off of the accelerator and let the vehicle coast down until it
stops under its own power as you complete your exit from the freeway. Do
not use the foot brake and do not shift gears until the very end of this
"coast down" phase.
Step Four: More City Driving
After you have completed the freeway trip, drive through the city
streets for a repeat of the second part of Step Two.
Go up to about 35 to 40 mph a few times and then maintain a city speed
of 25 mph before slowing down to stop. Again, don't roll through the
stop and make sure to accelerate normally.
Pull in to a parking place and let the engine idle for one to two
minutes and then shut it off.
Step Five: Have your Readiness Monitors Checked and Verified
Drive your vehicle to your regular shop and have them re-check your
readiness monitors, present codes, and pending codes. They should do
this as a courtesy and for free.
If all of your monitors are "ready" and there are no present or pending
codes, then your vehicle has been properly repaired and is ready for an
emissions inspection and for normal driving.
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