Abstract: There is provided vehicle diagnostic method and apparatus capable of reducing restrictions on the sequence and timing of operations to be performed by an operator for each diagnostic item.In the vehicle diagnostic apparatus, the actual vehicle state detected by the vehicle state detection apparatus 223 is compared with the expected state selected by the selection apparatus 222. For example, while the operator runs the vehicle on purpose to execute the "Vehicle Sensor Diagnosis", if an actual state (vehicle speed VS) is detected by the vehicle state detection apparatus 223, an expected state of the vehicle speed (reference vehicle speed VSref) will be selected by the selection apparatus 222. Then both states are compared by the comparison apparatus 224. When both states are identified as exhibiting an expected relation (e.g., correspondence), the comparison apparatus 224 makes the display 27 indicate that the diagnostic item 1 is passed. Specifically, the indication of "01" is erased from the display 27.