Vehicle Speed Sensor: Description and Operation

LOCATION
Sensor is mounted in transaxle extension housing.

PURPOSE
- The Powertrain Control Module (PCM) uses sensor input, when it receives a "closed throttle" input from the Throttle Position Sensor (TPS), to determine whether vehicle is decelerating or stopped.

- The PCM stores sensor input as distance traveled.

- The PCM uses sensor input to control speedometer.

OPERATION
- During idle, (no signals being received from sensor), the PCM actuates the Idle Air Control (IAC) motor to maintain desired engine idle speed.

- During closed throttle deceleration, (slower signals received from sensor), the PCM actuates the IAC motor to maintain desired Manifold Absolute Pressure (MAP) sensor value.

- Sensor generates 8 voltage pulses per axle shaft revolution.