Wheel Sensor 7/31, 7/32, 7/56, 7/57: Check

Prerequisites (unless otherwise specified):

NOTE: On special vehicles like police and taxi, all extra connected devices must be shut off as they may use any of the signal outputs in the table above.

Breakout box connected.
Sensor engaged.
Ignition switch position II.

Create a temporary voltage feed between #1 on the breakout box via a resistor of 1 kΩ and the sensor's signal output (#7, #9, #11, or 14). Connect a voltmeter between the sensor's signal output and ground connection #16. Turn the wheel slowly:

Tooth against sensor U ≈ U_Low

Gap against sensor U ≈ U_bat

Fig 1: Identifying Sensor Output

Courtesy of VOLVO CARS CORPORATION