The VSS (Vehicle Speed Sensor) is an electromagnetic sensor, which uses a rotating ring, in order to complete an input circuit to the Powertrain Control Module (PCM). It is located in the housing of the transmission, its position allows the reluctant ring to cross through it, as it is narrow.In turn, the reluctance ring secures the output shaft of the transmission whose purpose is for both to rotate.. When the ring passes through the electromagnetic tip of the Vehicle Speed Sensor, the teeth and slots have the function of completing and interrupting the circuit quickly. These manipulations of the circuit are translated by the Power Train Control Module (PCM) as vehicle speed.
Diagnostic code P0501 OBD2 is set when the PCM detects that the information sent by the VSS sensor, it means the speed of the vehicle, is concealed outside the expected range. It may be high or low in excess.