Ford Escort 1997 Owner's Manual page 159

(OBD) II system. If the vehicle's
powertrain system or battery has
just been serviced, the OBD II
system is reset to a not ready for
I/M testing condition. To ready the
OBD II system for I/M testing, the
law specifies that a minimum of 30
minutes of city and highway
driving is necessary as described
below:
• At least twenty minutes driving
in stop-and-go, city-type traffic
with at least four idle periods.
• At least ten minutes of driving
on an expressway or highway.
Before completing the above
driving modes, the engine must be
warmed up and at operating
temperature. Once started, the
vehicle must not be turned off
during these modes.
Maintenance and care
159