| Pos. | Spare part number | Name |
| 1 | - | Screw |
| 2 | - | Wheel speed sensor |
| 3 | - | Bearing seal and magnetic impulse wheel |
| 4 | - | Wheel bearing |
| 5 | - | Wheel hub |
An active wheel speed sensor is mounted on each wheel knuckle. They provide the ABS module with a speed signal from each wheel. The head of each wheel speed sensor is located close to a magnetic pulse wheel built into the wheel bearing seal. Each pulse wheel on the front axle bearings contains 44 north and south poles; each pulse wheel on the rear axle bearing has 48 pairs of poles. A connecting wire connects each sensor to the vehicle's wiring harness.
The wheel speed sensor receives electrical power from the ABS module and is also connected to it by an electrical signal circuit. When the ignition switch is in power mode 6 (ignition), the ABS module supplies power to the wheel speed sensors and monitors the return signals. The rotation of the wheels initiates current oscillations in the return signals of the speed sensors. The ABS module then converts the return signals into individual wheel speeds and overall vehicle speed.
The ABS module transmits individual wheel speeds and vehicle speed information via the high-speed CAN bus for use by other systems. Vehicle speed signal quality information is also transmitted via the high-speed CAN bus. If speed signals from all wheels are available to calculate vehicle speed, the vehicle speed signal quality is set to "calculated data within specified accuracy". If one or more wheel speed sensors are not functioning, the vehicle speed signal quality is set to "accuracy not within specified accuracy".
The ABS module monitors the electrical circuits of the wheel speed sensor for malfunctions. If a malfunction is detected, the ABS module stores the corresponding DTC in memory and the corresponding warning lamps are illuminated, depending on the functions in question (DSC/ETC, ABS, EBA/EBD, HDC). A warning chime also sounds to alert the driver of the malfunction.
On vehicles equipped with a "high series" instrument cluster, a message in the message center is only displayed if a fault affects the operation of the HDC.
For more information, please refer to the chapter:
- Instrument cluster (413-01 Instrument cluster, Description and operating principle)
- Information and Message Center (413-08 Information and Message Center, Description and Operating Principle)
Since the wheel speed sensors are active devices, there is a feedback signal when the wheels are not rotating. This allows the ABS module to check the status of the speed sensors when the vehicle is stationary.
Sensor block
| Pos. | Spare part number | Name |
| 1 | - | Sensor block |
| 2 | - | Stud and nut (2 pcs.) |
| 3 | - | Electrical connector |
The sensor package is mounted below the center console and is secured to the transmission tunnel with two studs and nuts. The sensor package is a compact unit that provides the ABS module with yaw rate, roll rate, longitudinal acceleration, and lateral acceleration input signals. The ABS module transmits the input signal values over the high-speed CAN bus for use by other systems.
When the ignition is in power mode 6 (ignition), the sensor unit receives ignition-on power from the ABS module. The sensor unit is also connected to the ABS module via a private CAN bus.
The article was copied from this resource LRMAN.RU
The sensor unit diagnostics are performed by the ABS module. If a sensor malfunction is detected, the ABS module stores the corresponding DTC in its memory and the corresponding warning lamps are illuminated, depending on the functions in question (DSC/ETC, ABS, EBA/EBD, HDC). A warning chime also sounds to alert the driver of the malfunction.
On vehicles equipped with a "high series" instrument cluster, a message in the message center is only displayed if a fault affects the operation of the HDC.
For more information, please refer to the chapter:
- Instrument cluster (413-01 Instrument cluster, Description and operating principle)
- Information and Message Center (413-08 Information and Message Center, Description and Operating Principle)
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