Trucking Accidents and the Engine Control Module (ECM), a.k.a. the “Black Box”

There’s two sides to every story and trucking accidents are no different. Typically when two vehicles are involved in an accident the vehicle drivers’ stories vary in some way. Law enforcement officials and insurance companies are left with the job of sorting through the facts to come up with an accurate picture of what happened, which is not an easy job.

Fortunately, when an accident involves a truck there is often an Engine Control Module (ECM), commonly known as a black box, to help establish what happened during the trucking accident. The data stored on the black box can be downloaded to serve as undisputed evidence of the crash events.

Most truck tractor manufacturers put some sort of ECM in the tractor to monitor the engine performance and various driver variables. How the data can be obtained from the black box varies by model, but typically the computer records all incidents of hard brake, engine revolutions, and if the truck’s clutch was engaged. Newer tractors may also be equipped with devices to monitor driver fatigue and to assist in avoiding rollover prevention. ECMs may also keep track of all vehicles driving ahead of the tractor and those driving in the truck’s blind spot. All of this information can prove invaluable when investigating an Illinois trucking accident.


However, in order to prove useful in an investigation the information stored on the black box must be accessed as soon after the truck crash as possible. At Kreisman Law Offices we make it a point to send certified letters to both the trucking company and the truck drivers involved notifying them that they are required to preserve both the ECM data and other relevant documents. This ensures that valuable information does not get lost or destroyed.

However, because not all trucks have the same type of information it is important to find out what sort of data is available. In order to determine whether or not a truck is equipped with an ECM, refer to the vehicle’s “line sheet” or “build sheets” which identify all the equipment on the tractor when it was delivered from its manufacturer.

Once the relevant information is obtained, the data found on the ECM can be used by experts to reconstruct the accident, the scene, and different versions of the trucking crash as given by the different drivers and witnesses.

Kreisman Law Offices has been handling Illinois trucking accident cases for over 30 years, serving the areas in and around Cook County including Oak Lawn, Chicago, Deer Park, and Schaumburg.