Enhanced Testing

C1203 - Wheel Speed Sensor: Front-RH Open/Short







General Description
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs. For example, rear wheel speed signal is used as a referecnce value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed. The wheel speed sensor generates sinewave signals, based on magnetic field made by a permanent magnet in the speed sensor, when the tone wheel rotates. The frequency and AC voltage changes in proportion to the wheel speed, and the HECU determines the speed by calculating the frequeny of the signal.

DTC Description
The ABS ECU monitors the wheel speed sensor circuit continuously. A direct current is supplied in the wheel-speed sensor by a power source in the input amplifier of the control unit. If the WSS circuit is broken, the input of the amplifier recognizes a potential shift caused by the supplied current and a fault is detected. The fault is assigned to the wheel by decoding the voltage of the SFA (sensor fault analog) output of the input amplifier. Since only single faults are decoded, the following identification priority applies in the event of multiple faults: ( FL > RR > RL > FR ) Warning lamp is turned OFF if the detected fault is not more than when the IG KEY is turned to ON again.


Detecting Condition





Wiring Schematic