Trip Definition

TRIP DEFINITION
For a component monitor to erase or turn off a MIL illumination for open/short diagnostics, the PCM must first recognize that the engine has operated for 2 minutes, 3 consecutive times, with no failures.

All system monitors, component rationality and functionality monitors have their own trip counters. Once the appropriate conditions have been met, the monitor will be run. If the monitor fails its test, the MIL will be illuminated after completion of the first or second failed test (1 trip or 2 trips). If conditions can be repeated for 3 consecutive trips with no malfunctions, the MIL will be turned off.

Anytime the MIL is illuminated, a DTC is stored. It takes three good trips without the condition present to extinguish the MIL. The DTC remains in PCM memory even though the MIL has been extinguished. Once the MIL is extinguished, the PCM must pass the diagnostic test for the most recent DTC for 40 warm-up cycles for the DTC to be erased from memory

A warm-up cycle can best be described by the following:
^ The engine must be running
^ A rise of 40°F in engine temperature must occur from the time when the engine was started
^ Engine coolant temperature must reach at least 160°F

Once the above conditions occur, the PCM is considered to have passed a warm-up cycle. Due to the conditions required to extinguish the MIL and erase the DTC, it is most important that after a repair has been made, all DTC's be erased and the repair verified.