Common OBD-II Terms: Trip

Technically, a trip is a key on-run-key off cycle in which all enable criteria for a given diagnostic is met, allowing diagnostic to run. Unfortunately, this concept is not quite that simple. A trip is official when all enable criteria for a given diagnostic are met. But because enable criteria vary from one diagnostic to another, the definition of trip varies as well. Some diagnostics are run when vehicle is at operating temperature, some when vehicle first starts up; some require that vehicle be cruising at a steady highway speed, some run only when vehicle is idle; some diagnostics function only when TCC is disabled. Some run only immediately following a cold engine start-up.

A trip then, is defined as a key on-run-key off cycle in which vehicle was operated in such a way as to satisfy enabling criteria for a given diagnostic, and this diagnostic will consider this cycle to be one trip. However, another diagnostic with a different set of enable criteria (which were not met) during this driving event, would not consider it a trip. No trip will occur for that particular diagnostic until vehicle is driven in such a way as to meet all enable criteria.