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Mack Trucks

Beginning in 1998, Mack engines began using an electronic control system known as the V-MAC III. Late model Mack engines are controlled by the V-MAC IV. These systems include two modules: A VECU (Vehicle Electronic Control Unit) and EECU (Engine Electronic Control Unit).

V-MAC III and IV contain two stored "Incidents." The event threshold for these Incidents to be recorded is normally a decrease in wheel speed of 10 miles per hour per second, but this threshold can be changed at the customer's request. In addition, Incidents are recorded when the engine speed increases rapidly.

Mack Incidents record event data for 15.8 seconds before the Incident and 16 seconds after the Incident. The data are reported in two-tenths-of-a-second (0.2 seconds) intervals, and speed is reported to the nearest whole mile per hour.

Mack Incident Reports include wheel speed, engine speed, and the status of up to eight “switches.” Usually among these switches are cruise control (on/off), service brake (on/off), and key switch (on/off).

It is important to note that Mack Trucks have not provided public access to their Incident Data. Mack ECUs must be physically removed from the truck and sent to Allentown, Pennsylvania. The cost of a data extraction performed by Mack is approximately $2,385, and both ECUs must be removed and sent. The service that is provided for this fee is the controlled extraction of the data.

• A sample of the EDR portion of a V-MAC III report (PDF)
• An example index of available Mack data (PDF)

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