940 SE L4-2320cc 2.3L SOHC Turbo VIN 87 B230FT (1991)
Wheel Speed Sensor: Description and Operation
Wheel Speed Sensor
Sensor/Pulse Wheel
Each ABS sensor measures the speed of the road wheel by detecting the rate of passage of the teeth on the sensor wheel.
In the case of the rear wheels, the value recorded is an average since only one sensor and sensor wheel is installed.