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.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
If power supply of the WSS input amplifier is not normal or the ABS control cycle is continued abnormally, if the exact fault location among 4 WSS can not be determined, This coed is set.
Item | Detecting Condition | Possible cause | |
Case1 | DTC Strategy | ● Signal motorning | ● Improper installation of wheel speed sensor ● Abnormal Rotor and wheel bearing ● Faulty Wheel speed sensor |
Monitoring Period | ● Continuous (If no under voltage, no BLS, no BLS failure is detected) | ||
Enable Conditions | ● When short cut between the wheel speed sensor supply and the battery. | ||
Fail Safe | ● Wheel speed sensor signals are not reliable. | ||
Case2 - ESP Only | DTC Strategy | ● Signal motorning | |
Monitoring Period | ● Continous | ||
Enable Conditions | ● The monitoring reports a failure if the ABS target slip is exceeded for a time period >= 10 s at one or more wheels. - If the driver brakes or the velocity is lower than 50 km/h(31 MPH) the detection time is increased to 60s. | ||
Fail Safe | ● Reduced function of the ESP system | ||
- Refer to case 3, 4 of C1202
Sensor Type | Output Voltage | Airgab | |
HIGH | LOW | ||
Active Type | 1.05V | 0.525V | 0.7 mm - Front 0.5 mm - Rear |
