Trip Definition

A trip has different meanings depending on what the circumstances are. If MIL is off, a trip is defined as when oxygen sensor monitor and catalyst monitor have been completed in the same drive cycle. When any emission related DTC is set, the MIL is turned on. When MIL is on, it takes 3 good trips to turn the MIL off. In this case it depends on what type of DTC is set to identify what a trip is.

If MIL is on and a DTC was set by fuel monitor or misfire monitor, the vehicle must be operated in SIMILAR CONDITIONS WINDOW for a specified amount of time to be considered a good trip. SIMILAR CONDITIONS WINDOW displays information about engine operation during a monitor. If a non-continuous OBD-II monitor such as: oxygen sensor monitor, catalyst monitor, purge flow monitor, leak detection pump monitor or oxygen sensor heater monitor fails twice in a row and turns on the MIL, re-running that monitor which previously failed on next engine start-up and passing the monitor is considered to be a good trip. If any other emission related DTC which is not an OBD-II monitor is set, a good trip is considered to be when oxygen sensor monitor or catalyst monitor have been completed, or 2 minutes of engine run times exists and oxygen sensor monitor and catalyst monitor have been stopped from running. Trips may be read on the scan tool. For additional information for trip displays on scan tool, see TRIP INDICATORS  .

It can take up to 2 failures in a row to turn on the MIL. After MIL is turned on, it takes 3 good trips to turn the MIL off. After MIL is off, the PCM will erase or clear the DTC after 40 warm-up cycles. A warm-up cycle is defined as the engine is started, an increase of 40°F (4°C) in engine coolant temperature exists after engine is started and engine coolant temperature reaches at least 160°F (71°C).