Automotive troubleshooting process integrates repairing activities that are executed through auto professionals when they note phenomenon or conditions and determine about inspections, instructions, or checks, so as to tackle the trouble that affects a car. This study is focused on the knowledge representation for the aim of decision making in automotive troubleshooting process for automotive braking system. To reach this purpose, there are three phases followed: (1) a knowledge representation with procedural mode is investigated from an aspect of decision making; (2) a simple, instinctive, and efficient architecture of automotive knowledge formalization is presented; (3) an approach to generate troubleshooting procedures is defined. A new form, named diagram of expanded transformation (DoET), to represent knowledge and depict three fundamental tiers of decision making in the present or future disposal: processing strategy, quantity, and inapplicability. The approach can be also utilized manually to create DoETs from auto repair manuals (ARMs) or to build them spontaneously applying the messages feasible on workshop lists regarding single, multi-tier troubleshooting processes. The DoETs with auto repair manuals for auto braking system is validated. The acquired model can be utilized as a base structure for troubleshooting assisted systems generation.