Trip and Warm-Up Cycle

TRIP

Description
The ability for a DTC to run depends largely upon whether or not a Trip has been completed. A Trip for a particular DTC is defined as vehicle operation, followed by an engine off period and a driving mode such that any particular DTC has had sufficient time to complete testing.

Operation
The requirements for trips vary as they may involve items of an unrelated nature; driving style, length of trip, ambient temperature, etc. Some DTCs run only once per trip (e.g. catalyst monitor) while others run continuously (e.g. misfire and fuel system monitors). If the proper enabling conditions are not met during that ignition cycle, the tests may not be complete or the test may not have run.


WARM-UP CYCLE

Description
In addition, the execution of a DTC may also be bound by conditions which must comprehend a Warm-up cycle. A Warm-up cycle consists of engine start-up and vehicle operation such that the coolant temperature has risen greater than a certain value (typically 40°F) from start-up temperature and reached a minimum temperature of 160°F. If this condition is not met during the ignition cycle, the DTC may not run.