Component Location
1. Wheel Speed Sensor
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.
Wheel speed sensor is active hall-sensor type.
DTC Description
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set when there is no wheel speed signals within 10ms to 20ms at a vehicle speed > 43.2km/h or a deviation between sensors exceed the threshold or one or two wheels are at 2.75km/h while the vehicle speed is at 12km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 12Km/h.(7.4mph)
DTC Detecting Condition
Item | Detecting Condition | Possible cause |
DTC Strategy | Signal monitoring
| Improper installation of wheel speed sensor Abnormal Rotor and wheel bearing Faulty Wheel speed sensor(FL) |
Case 1 (WSS signal monitoring on driving) | Monitoring Period | The first driving above 12kph(7.4mph). (remonitoring at 12 kph(7.4mph) in case of restarting after stop the car)
|
Enable Conditions | If one wheel is under 2.75kph(1.7mph) and the vehicle speed is above 12 kph(7.4mph)
|
Case 2 (WSS invalid signal monitoring) | Monitoring Period | Continuous (ecept the monitoring period of case 1)
|
Enable Conditions | Even though every wheel speed is normal in case of case 1, signal failure flag is set when under 2.75kph(1.7mph) from any wheels is detected during acceleration or deceleration from 12kph(7.4mph), a failure is set if the 2.75kph(1.7mph) on the same wheel is detected again at the time of speed when flag is set + 18kph(11.2mph) - Stop control right away if wheel speed senosor failure is detected during no control
|
Case3 (WSS differences monitoring) | Monitoring Period | Continueosly on driving
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Enable Conditions | If the following failure is detected caused by difference of wheel speed caused by airgap or missing teeth detection 1. FL/RL, FR/RR : 6~12kph(3.7~7.4mph), FL/FR : 10~16kph(6.2~12.4mph) Fault detection time : maximum 20s 2. FL/RL, FR/RR : >12kph(7.4mph), FL/FR : > 16kph(12.4mph) Fault detection time : maximum 10s 3. Fault detection time is maximum 80s when spin occurs on front wheel - Stop control right away if wheel speed senosor failure is detected during no control
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Fail Safe | One or two wheel speed sensor fault - Only the ABS/ESP functions are inhibited - The ABS/ESP warning lamps are activated and the EBD warning lamp is not activated
More than 2 wheel speed sensor fault - The ABS/EBD/ESP functions are inhibited - The ABS/EBD/ESP warning lamps are activated
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Specification
SensorType | Output Voltage | Air Gap |
HIGH | LOW |
Active Type | 1.4~2.0V | 0.7~1.0V | 0.4~1.0mm |
Diagnostic Circuit Diagram