Honda - Accord Prelude 1996 2000

Throttle Position Sensor

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OPERATION





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Fig. Cross-sectional view of a typical Honda Throttle Position (TP) sensor



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Fig. The Throttle Position (TP) sensor is mounted to the side of the throttle body

The Throttle Position (TP) sensor is a potentiometer that provides a signal to the ECM/PCM that is directly proportional to the throttle plate position. The TP sensor is mounted on the side of the throttle body and is connected to the throttle plate shaft. The TP sensor monitors throttle plate movement and position, and transmits an appropriate electrical signal to the ECM/PCM. These signals are used by the ECM/PCM to adjust the air/fuel mixture, spark timing and if installed, EGR operation according to engine load at idle, part throttle, or full throttle. The TP sensor is not adjustable.

The TP sensor receives a 5 volt reference signal and a ground circuit from the PCM. A return signal circuit is connected to wiper that runs on a resistor internally on the sensor. The further the throttle is opened, the further the wiper moves along the resistor. At full throttle, the wiper essentially creates a loop between the reference signal and the signal return returning the full or nearly full 5 volt signal back to the PCM. At idle the signal return should be approximately 0.9 volts.

The ECM/PCM compares the TP sensor with the MAP sensor to determine if the system is functioning properly.

TESTING





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Fig. The TP sensor can be monitored with an appropriate and Data-stream capable scan tool



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Fig. Output voltage vs. throttle opening of a Throttle Position (TP) sensor

  1. With the engine OFF and the ignition ON , check the voltage at the signal return circuit of the TP sensor by carefully backprobing the connector using a DVOM.
  2.  
  3. Voltage should be between 0.2 and 1.4 volts at idle.
  4.  
  5. Slowly move the throttle pulley to the Wide Open Throttle (WOT) position and watch the voltage on the DVOM. The voltage should slowly rise to slightly less than 4.8v at WOT.
  6.  
  7. If no voltage is present, check the wiring harness for supply voltage (5.0v) and ground (0.3v or less), by referring to your corresponding wiring guide. If supply voltage and ground are present, but no output voltage from TP, replace the TP sensor. If supply voltage and ground do not meet specifications, make necessary repairs to the harness or PCM.
  8.  

REMOVAL & INSTALLATION



On some models, the TP sensor is not removable from the throttle body. If the TP sensor goes bad, the entire throttle body must be replaced.

  1. Disconnect the negative battery cable.
  2.  
  3. Unplug the wiring harness from the TP sensor.
  4.  
  5. Remove the two sensor mounting screws.
  6.  
  7. Pull the TP sensor off the throttle shaft.
  8.  



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Fig. On this 1996 Accord, the TP sensor can be removed from the throttle body by detach the wiring, then unfasten the mounting screws

To install:

  1. Install the TP sensor onto the shaft.
  2.  
  3. Install and tighten the sensor mounting screws.
  4.  
  5. Attach the wiring harness to the sensor.
  6.  
  7. Connect the negative battery cable.
  8.  

 
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