Left Hand Drive

Vehicle Speed Sensor (VSS) Typical:

Vehicle Speed Sensor Location:

PURPOSE
The Vehicle Speed Sensor (VSS) located in the extension housing of the transmission, is used to inform Powertrain Control Module (PCM) of vehicle deceleration and engine idle. The PCM uses this information to control Idle Air Control (IAC) motor position during these conditions.

PCM uses sensor input with input from [1][2]Throttle Position Sensor (TPS) and VSS to differentiate between closed throttle deceleration or closed throttle idle.

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

During idle, PCM actuates the IAC motor to maintain desired engine idle speed.

VSS Circuit:

OPERATION
Theory of operation: The vehicle speed sensor is a hall-effect type sensor used to detect the vehicle speed. The PCM calculates the vehicle speed based on the VSS signal. The PCM supplies 8 volts from cavity 7 to power up the sensor. Sensor ground is supplied by PCM cavity 4. The PCM also supplies a 5.0 volt pull up voltage to the sensor from cavity 47. The VSS signal is created when the sensor alternates the 5.0 volt pull up from high to low.

CIRCUIT OPERATION
Circuit K7 supplies 8 Volts from the Powertrain Control Module (PCM) to the vehicle speed sensor. The K7 circuit connects to cavity 7 of the PCM.

Circuit G7 from the vehicle speed sensor provides an input signal to the PCM. The G7 circuit connects to cavity 47 of the PCM.

The PCM provides a ground for the vehicle speed sensor signal (circuit G7) through circuit K4. Circuit K4 connects to cavity 4 of the PCM.