GM Corvette 1984-1996 Repair Guide

Throttle Position Sensor

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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



  1. Visually check the connector, making sure it is properly attached 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 B for VIN 8 and J, or terminal C for VIN P & 5 engines. 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.  



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Fig. Fig. 1: Throttle Position (TP) sensor circuit-VIN 8 and J engines



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Fig. Fig. 2: Throttle Position (TP) sensor circuit-VIN P and 5 engines

  1. If the voltage is not within specification, check the 5 volt reference signal circuit at terminal C for VIN 8 & J engines or terminal A for VIN P & 5 engines 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 Figure 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: Typical Throttle Position (TP) sensor mounting

To install:
  1. With the throttle valve in the normal closed idle position, install the throttle position on the throttle body, making sure that sensor pickup lever lines up with the tang on the throttle actuator lever.
  2.  
  3. Place the TP sensor in position. Align the TP sensor lever with the sensor drive lever on the throttle body.
  4.  
  5. Install the TP sensor mounting screws and tighten to 18 inch lbs. (2 Nm).
  6.  
  7. Attach the electrical connector.
  8.  
  9. Connect the negative battery cable.
  10.  

 
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