Roadi RDT51 - Manual (Page 9)

OWNER S MANUAL
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OBD2 Car Scanner
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2.6 OBD II Definitions
Powertrain Control Module (PCM) -- OBD II terminology for the on-
board computer that controls engine and drive train.
Malfunction Indicator Light (MIL) -- Malfunction Indicator Light
(Service Engine Soon, Check Engine) is a term used for the lig ht on the
instrument panel. It is to alert the driver and/or the repair technician that
there is a problem with one or more of vehicle's systems and may cause
emissions to exceed federal standards. If the MIL illuminates with a steady
lig ht, it indicates that a problem has been detected and the vehicle should
be serviced as soon as possible. Under certain conditions, the dashboard
lig ht will blink or flash. This indicates a severe problem and flashing is
intended to discourage vehicle operation. The vehicle onboard diagnostic
system can not turn the MIL off until necessary repairs are completed or
the condition no longer exists.
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
throug h 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 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.