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after the battery has been disconnected. Running through a vehicle’s
complete drive cycle will “set” the readiness monitors so that future
faults can be detected. Drive cycles vary depending on the vehicle and
the monitor that needs to be reset. For vehicle specific drive cycle,
consult the vehicle’s Owner’s Manual.
Freeze Frame Data
-- When an emissions related fault occurs, the
OBD II system not only sets a code but also records a snapshot of
the vehicle operating parameters to help in identifying the problem.
This set of values is referred to as Freeze Frame Data and may
include important engine parameters such as engine RPM, vehicle
speed, air flow, engine load, fuel pressure, fuel trim value, engine
coolant temperature, ignition timing advance, or closed loop status.
