PURPOSE: To detect the abnormality of a brake switch rapidly and accurately by judging that the drive switch is abnormal when the detecting output of the brake switch indicates a non-operating condition in spite of indicating a sudden speed reduction of the vehicle running by the detecting output of a car speed sensor.
CONSTITUTION: An internal combustion engine 10 drives driving wheels 34 through a transmission 14. An ECU 50 inputs the detecting signals from a throttle opening sensor 40, a car speed sensor 42, a brake switch 44, a range selector switch 46, and the like, to an input circuit 50d respectively, and after a specific operation process is carried out in a CPU 50a, a control signal is output from an output circuit 50e to solenoid valves 54, 56, and the like of a shift valve. In this case, when the detecting output of the brake switch 44 indicates a non- operating condition of the brake, in spite of the condition that the detecting output of the car speed sensor 42 indicates a sudden speed reduction corresponding to the vehicle, it is decided that the brake switch 44 is abnormal, in the ECU 50. Consequently, an abnormal condition of the brake switch 44 can be detected rapidly and accurately.
SUNADA SATORU
MARUYAMA TAKAFUMI
FUKUSHI HIDEO
