Method for detecting output-stuck fault of car body acceleration sensor, apparatus for detecting output-stuck fault of car body acceleration sensor, and anti-lock braking system for car

By a method for detecting an output-stuck fault of a car body acceleration sensor, an absolute value of a relative difference between the logical car body acceleration operated on the basis of a wheel speed and the physical car body acceleration output from a car body acceleration sensor is obtained, and the obtained absolute value of the relative difference is compared with a first rated value. When the absolute value of the relative difference exceeds the first rated value, a fail counter is made to start to count up at that point of time. When a counted value of the fail counter exceeds one second during the absolute value of the relative difference is exceeding the first rated value, the difference of the maximum value and the minimum value of the physical car body acceleration during the period is compared with a second rated value. When the difference is less than the second rated value, it is judged that the car body acceleration sensor is in its output-stuck fault state in which the output of the sensor does not change to be left to be fixed.