When the unit is installed in the vehicle, it can then be set to coincide with the vehicle's specifications, such as RPM.
But the Mosinee Fire Department never programmed the ECM, so it never recorded any data.
"They're generally set to zero," says Lt. Tim Carnahan of the Wisconsin State Patrol. "The end user makes arrangements either with the dealership or manufacturer to set the parameters. With a commercial engine in an ambulance, which is not a commercial carrier, I don't think it would be unusual to have the parameters left at zero."
Carnahan says ambulances are not required to program the ECMs.
Also, the Mosinee Fire Department has a policy of not exceeding the speed limit by 10 miles per hour.
But since no data was recorded, it may not ever be known how fast the ambulance was going when it crashed.