Circuit Operation

The Vehicle Speed Sensor is a gear-driven permanent magnet generator housed in the vehicle's transaxle. This sensor generates a sine wave output with a frequency proportional to the vehicle speed. The PCM converts this signal to an output that is switched to ground at a frequency of 4000 pulses per mile at the DK GRN wire (CKT 389), which feeds the Instrument Panel Cluster. The PCM also produces an output at the DK GRN/WHT wire (CKT 817) which feeds the Speed Sensitive Suspension Module (4.9L Powertrain) or Road Sensing Suspension (RSS) Module (Northstar Powertrain).