Fault diagnostic system for vehicles using identification and program codes

A fault diagnostic system for connection to a computer-aided electronic control unit carried on a vehicle for detecting and diagnosing faults in vehicle parts connected to said electronic control unit, said fault diagnostic system comprising:

• means for providing a control unit identification code that identifies the type of electronic control unit that is being carried on the vehicle;
• means for providing a vehicle identification code that identifies the type of vehicle on which the electronic control unit is being carried;
• storage means for storing a plurality of diagnostic programs;
• a priority table in which a fault code and diagnostic priority are assigned for an electronic control unit fault and for each faulty vehicle part respectively;
• abnormality detecting means for detecting abnormality of said electronic control unit and vehicle parts and outputting a fault code corresponding to each abnormality;
• means responsive to detection of a plurality of abnormalities for accessing said priority table using the plurality of fault codes output from said abnormality detecting means as retrieval keys, and displaying the fault codes corresponding to said abnormalities along with said priority;
• and
• program selecting means jointly responsive to said control unit identification code, to said vehicle identification code, and to a fault code and priority selected by an operator from said display for retrieving one of said diagnostic programs from said storage means for use by said fault diagnostic system.