Method and apparatus for detecting faulty operation of a wheel speed sensor

摘要

Faulty operation of a two-lead wheel speed sensor in a vehicle control system is detected and distinguished from transients by measuring a common mode voltage of the sensor and applying such voltage to a window comparator. Analog-to-digital conversion circuitry for capturing wheel speed signals is disabled so long as the measured voltage falls outside the comparator window. When the measured voltage is outside the comparator window for at least a given time limit, an open circuit fault condition is indicated. Additionally, the sensor lead voltages are compared to threshold voltages; when both voltages exceed the thresholds for at least a given time limit, a short circuit fault condition is indicated. The windows, thresholds and time limits are programmable by the vehicle control system computer.