ENGINE DIAGNOSTIC UNIT

PROBLEM TO BE SOLVED: To solve a problem that although a conventional diagnostic unit judges according to operation condition of an engine whether it is a condition allowing diagnosis and performs the diagnosis when judging the condition allowing diagnosis, the engine operation condition depends on a driving situation of a driver and a traveling situation of a vehicle and the diagnosis may not be made once from after engine start until engine stop. SOLUTION: A vehicle diagnostic unit according to the invention comprises a means for controlling the engine and a second wheel drive force controlling means provided separately from the engine and controls the engine and the second wheel drive force controlling means provided separately from the engine so that the diagnostic condition is satisfied when diagnosis performing frequency is less. Thereby, the vehicle diagnostic unit allows the engine diagnosis regardless of a driving method of the driver and the vehicle traveling situation. COPYRIGHT: (C)2006,JPO&NCIPI