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 and good at temperature and noise chariteristic. Digital wave is produced as tone wheel rotate according as hall sensor principle.
Frequency of duty wave is changed in proportion to rotation of tone wheel and HECU calculate vehicle speed by this frequency.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set, if there is current flow into wheel speed sensor imput amplfier or the ABS control cycle is continued abnormally.
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 ● Faulty HECU |
Monitoring Period | ● Continous | ||
Enable Conditions | ● When short cut between the wheel speed sensor supply and the battery. | ||
Fail Safe | ● Wheel speed sensor signals are not reliable. | ||
Case2 | 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 the detection time is enlarged to 60s. | ||
Fail Safe | ● Reduced function of the ESP system |
