Hi,

the sensor you have found is probably the 'rough road sensor'.
The ecu uses this wheel speed sensor to determine as it's name implies bad road surfaces which can cause transmission snatch.
This can leads to variations in crankshaft speed which in turn may be seen by the ecu as a engine misfire. The ecu can then inhibit the misfire diagnostics under various road conditions or if the signal is constant (rough road sensor) use this as a proof for engine misfire diagnostics.

HTH

Teckie2