Wheel speed sensor
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.
The sensors are active, which means that they have a built in electronic circuit. The control module transmits a voltage of U bat , the sensor sends back a digital power signal of 7 or 14 mA, depending on position. This solution gives a more robust signal, compared to the voltage signal. The current flow over the connections is higher which minimizes the chance of corrosion.