Représentations et fonctionnements cognitifs dans une recherche de panne d’un système d’allumage en mecanique-auto

Fault finding is a puzzling task, at work and in technical and professional training. Our purpose is to contribute to an analysis of the required competencies and mainly to a characterisation of the evolution steps in knowledge and action organisation from novice to expert. Eight grown-up preparing a professional certificate in engine mecanics were observed and filmed while they were working out the diagnosis of an ignition trouble on a real equipment. The theory of functionning registers (deducted from Piaget’s theory) is considered as a relevant frame for our activity analysis. So, four competencies patterns has been outlined on the basis of errors extension, circuit functionning representations which were infered from schema interpretations, and trouble-shooting strategies denoted by control procedures. Some consequences about training are examined.