Component Operation

With the ignition switch in ON (II) or START (III), battery voltage is supplied from fuse 22 through the BLK/YEL wire to the vehicle speed sensor (VSS). The sensor is grounded by the GRN/WHT wire to the Engine Control Module (ECM) or Powertrain Control Module (PCM). The speedometer and other control units in the circuit supply about 5 volts to the YEL/RED wire. The vehicle speed sensor (VSS) intermittently grounds the YEL/RED wire which generates a pulsed signal in it. The number of pulses per minute increases/decreases with the speed of the car.