Troubleshooting information for the Iltis Canadian Military Truck is in short supply. The applicable Canadian Forces Technical Orders are limited to one copy for each maintenance workshop and the personnel reductions recently experienced by the Canadian Forces has resulted in a need for greater efficiency in the workplace. The need for a troubleshooting aid for the vehicle was investigated. Since Maintenance Manuals in use are limited in number and time-consuming to update, a computer-based system was considered. A diagnostic software tool was designed that mirrored the function of the existing repair manuals. A programme was developed that could be used as a model for future development of computer-based diagnostic tools within the Canadian Armed Forces. A description of the needs analysis, the expert system shell used to develop the software, and the diagnostic tool are included. / Master of Science