Car engine electronic control unit tuning is a tedious and difficult task. Engineers can no more check on-line the measurements validity: Control strategies are becoming more complex and measurements more numerous. A fault diagnosis approach relying on experts' qualitative and uncertain knowledge has been developed to identify whenever a malfunction is present. The theoretical framework -based on possibility theory and on consistency and abductive indices -is first explained. The latest results are then presented. Finally, the whole incremental development process of the prototypes is described, explaining the most difficult points and how they were handled.

No abstract