Vehicle Speed Sensor

Vehicle Speed Sensor:

PURPOSE
The sensor input is used by the Powertrain Control Module (PCM) to determine vehicle speed and distance traveled.

OPERATION
The speed sensor generates 8 pulses per sensor revolution. These signals, in conjunction with a closed throttle signal from the throttle position sensor (auto. trans. only), indicate a closed throttle deceleration to the PCM. When the vehicle is stopped at idle, a closed throttle signal is received by the PCM (but a speed sensor signal is not received).

In addition to determining distance and vehicle speed, the output from the sensor is used to help control:

Speed control operation
Transmission overdrive operation
Transmission torque converter electrical operation