Citation

Little D. Collision 2007; 2(2): 42-45.

Copyright

(Copyright © 2007, Collision Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Although General Motors sensing diagnostic modules (SDMs) do not provide a time clock, they do report the number of times the ignition has been turned on (the ignition cycles), which can be used to approximate the time between the event that was recorded and the date of the investigation. The average daily ignition cycles can also be used to determine if there is likely to be any data in a nondeployment event file (or if it may have been erased), given the time delay between the event and the start of an investigation. This paper reports on a retrospective study that was conducted to determine the average daily ignition cycles for GM vehicles over the life of the vehicle. The study of 135 vehicles revealed that the average ignition cycles for vehicles that were not used commercially were between 6 and 7 per day. Taxis had considerably higher number of ignition cycles, with an average and median of 24 to 26 ignition cycles per day.