Here's a bit more info from The Standard Motor web site.
So what does P1000 mean? A P1000
code means that ALL of the OBD II
monitors have not been completed
since the ECM���?�s memory has been
cleared. It is not necessary to clear
the P1000 code unless you are
performing a state inspection that
requires it to be cleared. This code
could also be the result of the
customer���?�s driving pattern not
permitting all of the OBD II monitors
to complete their drive cycle.
A Ford OBD II drive cycle is a
specific driving pattern which is used
to allow the various OBD II monitors
to run and be completed. The
requirements for the drive cycle to
complete are that all ���?Trip�� monitors
are completed. A trip is defined as an
engine running, vehicle moving, and
the ���?Trip�� monitor has been
completed. Therefore, if all OBD II
trips have been completed, you have
successfully completed the OBD II
drive cycle. All scanners will display
���?Trip Status�� as a ���?Yes�� or ���?No��. A
���?Yes�� simply means that a monitor
has run.
Regarding monitors, 1994 & 1995
Ford vehicles use five separate
monitors. 1996 & later vehicles use
as many as nine. Each monitor has
its own criteria to run and complete.
Each monitor is actually a test of a
particular system���?�s ability to meet
and stay within operating parameters.
When ALL of the monitors have run,
the P1000 code will be erased. It is
best to refer to the specific model���?�s
manual to determine the exact drive
cycle procedure. When performing a
drive cycle, a smooth, steady foot on
the accelerator will be to your
advantage in completing the cycle.
Abrupt speed changes and erratic
changes in TPS voltage will cause
the ECM to take longer to complete,
and may even abort certain tests.
Avoid wide-open throttle, and
exercise caution while driving and
viewing the scan tool. Most of the
scan tools will indicate each
monitor���?�s status, and whether or not
it has been completed. Some
monitors are run continuously, and as
a result will not indicate a completed
status. If for some reason a ���?trip�� was
not completed during a drive cycle,
the ECM will not need to re-run all of
the monitors. It will begin where it
had left off, so it is not necessary to
repeat the entire process.
With OBD II if you perform a repair
and want to verify that you did repair
the vehicle, you must keep in mind:
the system���?�s criteria for setting a
code, and whether the ECM is
looking for two consecutive faults. If
this is the case, then it���?�s mandatory
to view the monitor���?�s status and
make sure it���?�s completed. Don���?�t rely
on the MIL light, because it may take
two trips to come on, and that second
trip will be when the customer is
driving the vehicle.
Mike Nieto-
Ford Specialist
Hope this helps some.