Loading ...
Loading ...
Loading ...
4
LAUNCH Professional 919E User Manual
dierent part of the engine or emissions system, the “Trip Drive Cycle” needed
for each individual Monitor to run and complete varies.
Drive Cycle -- A specic 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 specic drive cycle, consult the service manual.
Note: Do not confuse a “Trip” Drive Cycle with an OBD II Drive Cycle. A
“Trip” Drive Cycle provides the “Enabling Criteria” for one specic Monitor to
run and complete its diagnostic testing. An OBD II Drive Cycle must meet the
“Enabling Criteria” for all Monitors on a particular vehicle to run and complete
their diagnostic testing.
Warm-up Cycle - Vehicle operation after an engine o 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 cycles as a
counter to automatically erase a specific code and related data from its
memory. When no faults related to the original problem are detected within a
specied number of warm-up cycles, the code is erased automatically.
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 dierences and gradual changes that occur over time.
1.4 Diagnostic Trouble Codes (DTCs)
OBD II Diagnostic Trouble Codes are codes that are stored by the on-board
computer diagnostic system in response to a problem found in the vehicle.
These codes identify a particular problem area and are intended to provide
you with a guide as to where a fault might be occurring within a vehicle. DO
NOT replace parts based only on DTCs without rst consulting the vehicle’s
service manual for proper testing procedures for that particular system, circuit
or component.
Loading ...
Loading ...
Loading ...