Vehicle Speed Sensor

The vehicle speed sensor is located on transmission extension housing (2WD models) or on transfer case extension housing (4WD models). The PCM uses vehicle speed (distance) sensor to detect if vehicle is moving and at what speed it is moving.

The sensor is an 8-pole switch which provides a pulse or switching rate, proportional to vehicle speed, to the PCM. By comparing the number of pulses to time elapsed, the PCM determines vehicle speed and distance traveled.

The vehicle speed sensor generates 8 pulses per sensor revolution. This signal, along with a closed throttle signal from the TPS sensor, indicates a closed throttle deceleration to the PCM.

Under deceleration conditions, PCM adjusts the Idle Air Control (IAC) motor to maintain desired MAP value. During idle (vehicle stopped), the PCM receives no signal from the vehicle speed sensor. The PCM adjusts the IAC motor to maintain a desired engine speed.

The vehicle speed (distance) sensor input is used to maintain speed (cruise) control operation and also as a reference for Service Reminder Indicator (SRI) light.