Onboard Diagnostics
DIAGNOSTIC TROUBLE CODES (DTCs)
“Enabling Criteria.” The requirements and procedures vary for each
Monitor. Some Monitors only require the ignition key to be turned “On” for
them to run and complete their diagnostic testing. Others may require a set
of complex procedures, such as, starting the vehicle when cold, bringing it
to operating temperature, and driving the vehicle under specific conditions
before the Monitor can run and complete its diagnostic testing.
¾ Monitor Has/Has Not Run - The terms “Monitor has run” or “Monitor has
not run” are used throughout this manual. “Monitor has run,” means the
PCM has commanded a particular Monitor to perform the required
diagnostic testing on a system to ensure the system is operating correctly
(within factory specifications). The term “Monitor has not run” means the
PCM has not yet commanded a particular Monitor to perform diagnostic
testing on its associated part of the emissions system.
¾ Trip - A Trip for a particular Monitor requires that the vehicle is being
driven in such a way that all the required “Enabling Criteria” for the Monitor
to run and complete its diagnostic testing are met. The “Trip Drive Cycle”
for a particular Monitor begins when the ignition key is turned “On.” It is
successfully completed when all the “Enabling Criteria” for the Monitor to
run and complete its diagnostic testing are met by the time the ignition key
is turned “Off.” Since each of the eleven monitors is designed to run
diagnostics and testing on a different part of the engine or emissions
system, the “Trip Drive Cycle” needed for each individual Monitor to run
and complete varies.
¾ OBD 2 Drive Cycle - An OBD 2 Drive Cycle is an extended set of driving
procedures that takes into consideration the various types of driving
conditions encountered in real life. These conditions may include starting
the vehicle when it is cold, driving the vehicle at a steady speed (cruising),
accelerating, etc. An OBD 2 Drive Cycle begins when the ignition key is
turned “On” (when cold) and ends when the vehicle has been driven in
such a way as to have all the “Enabling Criteria” met for all its applicable
Monitors. Only those trips that provide the Enabling Criteria for all Monitors
applicable to the vehicle to run and complete their individual diagnostic
tests qualify as an OBD 2 Drive Cycle. OBD 2 Drive Cycle requirements
vary from one model of vehicle to another. Vehicle manufacturers set
these procedures. Consult your vehicle’s service manual for OBD 2 Drive
Cycle procedures.
Do not confuse a “Trip” Drive Cycle with an OBD 2 Drive Cycle. A
“Trip” Drive Cycle provides the “Enabling Criteria” for one specific
Monitor to run and complete its diagnostic testing. An OBD 2 Drive
Cycle must meet the “Enabling Criteria” for all Monitors on a
particular vehicle to run and complete their diagnostic testing.
D900 CanScan 17
¾ Warm-up Cycle - Vehicle operation after an engine off period where
engine temperature rises at least 40°F (22°C) from its temperature before
starting, and reaches at least 160°F (70°C). The PCM uses warm-up
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