| 摘要 |
PROBLEM TO BE SOLVED: To enable surely diagnosing whether there is abnormality of an interconnection from a wheel speed sensor and a waveform shaping circuit which shapes the waveform of a wheel speed pulse. SOLUTION: A signal line 5 which connects a wheel speed sensor 2 with a waveform shaping circuit 3 which slices the output of the wheel speed sensor 2 is connected with a DC power supply Vcc via a variable resistor Rv. At the time of diagnosing, a resistance value of the variable resistor Rv is changed, and the output amplitude of the waveform adjusting circuit 3 is watched. When change is not observed in the output amplitude, abnormality warning is outputted considering the state that abnormality is generated in the signal line 5 or the waveform shaping circuit 3. When the signal line 5 which connects the wheel speed sensor 2 with the waveform shaping circuit 3 generates abnormality such as disconnection and ground shortcircutting, or the waveform shaping circuit 3 which slices the output of the wheel speed sensor 2 and shapes the waveform generates abnormality, and the waveform shaping output vanishes, the fact that the cause of generation of abnormality is in the signal line 5 or the waveform shaping circuit 3 can be delivered with an abnormality alarm, by changing the resistance value of the variable resistor Rv, according to a command from an operating equipment 12 as a diagnosing means. |
