The throttle position sensor mounts to the side of the throttle body. The sensor 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 0.6 volt at minimum throttle opening (idle) to a maximum of 4.5 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.
- Disconnect the negative battery cable.
- Disconnect the air plenum.
- Disconnect the TPS electrical connector.
- Remove the TPS mounting screws.
- Remove the TPS.
- After installing the TPS, the throttle plate should be closed. If the throttle plate is open, install the sensor on the other side of the tabs in the socket.
- Attach electrical connector to the TPS.
- Install air plenum and tighten the clamp.
- Connect the negative battery cable.
The Throttle Position Sensor (TPS) can be tested with a digital voltmeter. The center terminal of the sensor is the output terminal.
- With the ignition switch in the ON position, check the output voltage at the center terminal wire of the connector. Check the output voltage at idle and at wide open throttle (WOT). At idle, TPS output voltage should be greater then 0.6 volts. At wide-open throttle, TPS output voltage should be less than 4.5 volts. The output voltage should gradually increase as the throttle plate moves slowly from idle to WOT. Check for spread terminals at the sensor and PCM connections before replacing the TPS.