DTC P0502: VSS Circuit - Low Input (M/T Without Abs): Description

Vehicles equipped with M/T without anti-lock brakes receive vehicle speed from a right front wheel speed sensor. Right front wheel speed sensor produces an AC voltage of different amplitude and frequency depending on velocity of right front wheel. Sensor produces a readable AC voltage signal when vehicle speed is more than 3 MPH. Speed signal is sent to a wheel speed signal conditioner module, which converts AC voltage of sensor to a square wave. Square wave is produced by condition module grounding White wire from PCM, which is pulled up to 5 volts through a resistor on PCM. DTC sets when PCM does not detect a square wave vehicle speed signal for a certain length of time.