Throttle Position Sensor: Description and Operation

Fig 13 Throttle Position Sensor:

THROTTLE POSITION SENSOR (TPS)
The TPS mounts to the side of the driver side throttle body (Fig. 13). The TPS connects to the throttle blade shaft. The TPS is a variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage). The signal represents throttle blade position. As the position of the throttle blade changes, the resistance of the TPS changes.

The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the powertrain control module) represents throttle blade position. The TPS output voltage to the PCM varies from 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.

Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating conditions. The PCM also adjusts fuel injector pulse width and ignition timing based on these inputs.

CIRCUIT OPERATION
From the Powertrain Control Module (PCM), circuit K7 supplies 5 volts to the Throttle Position Sensor (TPS). Circuit K7 connects to cavity A17 of the PCM connector.

Circuit K22 delivers the TPS signal to the PCM. Circuit K22 connects to cavity A23 of the PCM connector.

The PCM provides a ground path for the TPS signal (circuit K22) through circuit K4. Circuit K4 connects to cavity A4 of the PCM connector.