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DTC -- Diagnostic Trouble Codes (DTC) that identify which section of the emission control
system has malfunctioned.
Enabling Criteria --Also termed Enabling Conditions. They are the vehicle-specific events
or conditions that must occur within the engine before the various monitors will set,or run.
Some monitors require the vehicle to follow a prescribed "drive cycle" routine as part of the
enabling criteria. Drive cycles vary among vehicles and for each monitor in any particular
vehicle.
OBD II Drive Cycle -- A specific mode of vehicle operation that provides conditions
required to set all the readiness monitors applicable to the vehicle to the "ready" condition.
The purpose of completing an OBD II drive cycle is to force the vehicle to run its onboard
diagnostics. Some form of a drive cycle needs to be performed after DTCs have been
erased from the PCM's memory or 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.
3. Using the Scan Tool
3.1 Tool Description
