Throttle Position Sensor: Description and Operation

FUNCTION
This sensor is used to send input signals to the Powertrain Control Module (PCM) to indicate the current angle of the throttle blade.

THEORY/OPERATION
This sensor is a variable resistor that has a 5 volt reference signal applied to it by the PCM. The Throttle Position Sensor (TPS) sends signals back to the PCM in the range of approximately 0.38 volts to 1.03 volts at minimum throttle opening (idle), to a maximum of 3.1 volts to 4.0 volts at wide open throttle (WOT), depending upon the throttle shaft angle. The PCM uses these input voltages to determine the current position of the throttle.

The PCM uses the voltage signals from the TPS and other input sensors to determine the proper air/fuel mixture and ignition timing for certain operating conditions. Some of these operating conditions are: acceleration, deceleration, idle, and wide open throttle.

TYPICAL READINGS
An input voltage of approximately 1 volt indicates a minimum throttle opening, idle, or deceleration condition. An input voltage of approximately 2 volts indicates a cruise or light acceleration condition. An input voltage of approximately 4 volts would indicate a maximum throttle opening or wide open throttle condition.

CIRCUIT OPERATION
From the Powertrain Control Module (PCM), circuit K6 supplies 5 Volts to the Throttle Position Sensor (TPS). Circuit K6 connects to cavity 61 of the PCM connector.

The K22 circuit delivers the TPS signal to the PCM. Circuit K22 connects to cavity 35 of the PCM connector. This circuit is spliced and provides an input to the Transmission Control Module (TCM) on throttle position.

The PCM provides a ground path for the TPS signal (circuit K22) through circuit K4. Circuit K4 connects to cavity 43 of the PCM connector.