The Throttle Position Sensor, or TPS is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine fuel delivery volume.
The TPS is a potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM to measure the voltage from the TPS.
As the throttle valve angle is changed (accelerator pedal moved), the output of the TPS also changes. At a closed throttle position, the output of the TPS is low (approximately 0.5 volts). As the throttle valve opens, the output increases so that, at wide-open throttle, the output voltage should be above 3.9 volts.
By monitoring the output voltage from the TPS, the PCM can determine fuel delivery based on throttle valve angle (driver demand).
See Figures 1, 2 and 3
Before testing any electrical component, inspect the wiring and connectors for damage. Also wiggle the connectors to ensure a that they are firmly engaged.
- Unplug the Throttle Position Sensor (TPS) electrical connector.
- Turn the ignition switch ON .
- Check the output voltage at idle and at wide open throttle.
- At idle the TPS output should be greater than 0.6 volts at wide open throttle the output voltage should be less than 4.5 volts.
- The output voltage should gradually increase as the throttle plate slowly opens from idle to wide open throttle.
- Check all of the electrical connections and ensure they are properly engaged.
REMOVAL & INSTALLATION
See Figures 4, 5, 6, 7, 8 and 9
The Throttle Position Sensor (TPS) attaches to the throttle body.
- Disconnect the negative battery cable.
- Remove the electrical connector from the throttle position sensor.
- Remove the throttle position sensor mounting screws.
- Lift the throttle position sensor off of the throttle shaft.
- The throttle end shaft end of the throttle body slides into a socket in the TPS. The socket has two tabs inside it. The throttle shaft rests against the tabs. When indexed correctly, the TPS can rotate clockwise a few degrees to line up the mounting screw holes with the screw holes in the throttle body. The TPS has a slight tension when it is rotated into position. If it seems to be difficult to rotate the TPS, install the sensor with the throttle shaft on the other side of the tabs in the socket. Tighten the mounting screws to 25 inch lbs. (3 Nm).
- After installing the TPS, the throttle plate should be closed. If the plate is open, install the sensor on the other side of the tabs in the socket.
- Attach the electrical connector to the TPS.
- Connect the negative battery cable.