FAULT DIAGNOSIS OF CONTROLLER FOR VEHICLE

PURPOSE:To achieve fault diagnosis without giving sense of instability to a driver by providing a changing means for changing the condition of fault judgment from a fault judgment means in the direction where the result of fault judgment is output soon, for a specific period of time, to carry out diagnosis for a point of fault memorized in a memory means at the time of starting operation of a controller after an engine is re-started. CONSTITUTION:When fault judgment is carried out by a fault judgment means 32, a sensor, for which fault is judged is recognized and memorized by a memory means 34, and the memory is retained until a controller is started to be activated after an engine is re-started. The condition of fault judgment is changed in the direction where the result of fault judgment is output soon, by a fault judgment means 32, for a specific period of time, to carry out diagnosis for a fault sensor stored in the memory of the memory means 34, by a judgment condition changing means 35, at the time of activation of the controller after the engine is re-started. It is diagnosed fast and accurately whether the fault judgment is caused by true fault of the controller by judging fault in the condition different from the fault judgment at the time of re-starting the engine.