iCarsoft HD I, Руководство пользователя

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Heavy Duty Diagnostic Tool HD I User’s Manual
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. Please
refer to the vehicle’s factory service manual for specific enabling procedures.
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 service 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.
Fuel Trim (FT) - Feedback adjustments to the base fuel schedule. Short-term
fuel trim refers to dynamic or instantaneous adjustments. Long-term fuel trim
refers to much more gradual adjustments to the fuel calibration schedule than
short-term trim adjustments. These long-term adjustments compensate for
vehicle differences and gradual changes that occur over time.