GM Corsica/Beretta 1988-1996 Repair Guide

Throttle Position Sensor (TPS)

Print

OPERATION



The TP sensor is mounted to the throttle body, opposite the throttle lever and is connected to the throttle shaft. Its function is to sense the current throttle valve position and relay that information to the PCM. Throttle position information allows the PCM to generate the required injector control signals. The TP sensor consists of a potentiometer which alters the flow of voltage according to the position of a wiper on the variable resistor windings, in proportion to the movement of the throttle shaft.

TESTING



Except 1996 2.2L Engines and 1994-96 3.1L Engines

See Figure 1

  1. Visually check the connector, making sure it is connected properly and all of the terminals are straight, tight and free of corrosion.
  2.  
  3. Connect a voltmeter to a known good engine ground and TPS terminal A (reference signal). Turn the ignition switch to the ON position to check the reference voltage:
    1. If 4.5-5.5 volts are present at terminal A, proceed to the next step.
    2.  
    3. If the voltage is outside of specifications, check the reference circuit.
    4.  

  4.  
  5. Connect a voltmeter to the TPS connector terminal C (TPS signal voltage) and to terminal B (sensor ground).
  6.  
  7. Turn the ignition switch to the ON position, with the engine OFF .
  8.  
  9. Check the TPS voltage with the throttle in the fully closed position, then operate the throttle to the full open position, while watching the voltmeter.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Throttle Position (TP) sensor circuit - except 1996 2.2L Engines and 1994-96 3.1L Engines

  1. For 2.0L, 2.2L, 2.8L and 3.1L engines, note the following:
    1. If the voltage at closed throttle is 0.2-0.9 volts and has a smooth increase to 4.5-4.7 volts when the throttle is fully open, the TPS is operating normally.
    2.  
    3. If the voltage at closed throttle is below 0.2 volts, replace the TPS.
    4.  
    5. If the voltage at wide open throttle increases above 4.7 volts, replace the TPS.
    6.  

  2.  
  3. For 2.3L engines, note the following:
    1. If the voltage at closed throttle is 0.29-0.98 volts and has a smooth increase to 4.5-4.7 volts when the throttle is fully open, the TPS is operating normally.
    2.  
    3. If the voltage at closed throttle is below 0.29 volts, replace the TPS.
    4.  
    5. If the voltage at wide open throttle increases above 4.8 volts, replace the TPS.
    6.  

  4.  

1996 2.2L Engines and 1994-96 3.1L Engines

See Figure 2

  1. Visually check the connector, making sure it is connected properly and all of the terminals are straight, tight and free of corrosion.
  2.  
  3. With the ignition in the ON position, check the voltage at terminal C. The voltage should read less that 0.5 volts.
  4.  
  5. Operate the throttle, while watching the voltage. The voltage should increase smoothly to 5 volts as the throttle is opened.
  6.  



Click image to see an enlarged view

Fig. Fig. 2: Throttle Position (TP) sensor circuit - 1996 2.2L Engines and 1994-96 3.1L Engines

  1. If the voltage is not within specification, check the 5 volt reference signal circuit at terminal A and ground the circuit at terminal B for the proper signal. If the correct signal is found, the sensor is faulty. If the proper signal is not found, check the circuits back to the computer control module for continuity.
  2.  
  3. If the circuits are functional, the PCM may be faulty.
  4.  

REMOVAL & INSTALLATION



See Figures 3

  1. Disconnect the negative battery cable.
  2.  
  3. Detach the TPS electrical connector.
  4.  
  5. Remove the mounting screws.
  6.  
  7. Remove the TPS and, if equipped, sensor seal from the throttle body.
  8.  



Click image to see an enlarged view

Fig. Fig. 3: Exploded view of the Throttle Position (TP) sensor - 2.0L and 2.2L (VIN G) engines

To install:
  1. Place the TP sensor in position. Align the TP sensor lever with the sensor drive lever on the throttle body.
  2.  
  3. Install the TP sensor mounting screws and tighten to 18 inch lbs. (2 Nm).
  4.  
  5. Attach the electrical connector.
  6.  
  7. Connect the negative battery cable.
  8.  

 
label.common.footer.alt.autozoneLogo