The tool stops recording when the key is off. Each time the key is cycled the unit builds a new trip. Once you print out the four page report you can look at information from each individual drive cycle (trip). As a code sets the trip turns red so you can easily pick out the trip in which the code actually set.
If used for the purpose intended it is a very effctive tool.
Thanks coyote...this noted and yes..it's a great tool for those cases when monitoring live data over several days is not a doable proposition. Hope all is well with you and your family. Go out and vote!