Mazda B-Series 1998-06

Throttle Position Sensor

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Operation



The Throttle Position (TP) sensor is a potentiometer that provides a signal to the 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 PCM. These signals are used by the PCM to adjust the air/fuel mixture, spark timing and EGR operation according to engine load at idle, part throttle, or full throttle. The TPS is not adjustable.



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Fig. Typical Throttle Position (TP) sensor mounting on the throttle body

The TPS is a variable resistor. As the accelerator pedal is depressed and released, the resistance inside the sensor changes. The computer uses this reading to determine proper air/fuel mixture and ignition timing settings.

Removal & Installation



  1. Disconnect the negative battery cable.
  2.  



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Fig. To remove the TP sensor, first disconnect the wire harness plug from the sensor



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Fig. If the mounting holes of the sensor are slotted, mark its position. Note: factory sensors are not slotted

  1. Disengage the wiring harness connector from the TP sensor.
  2.  
  3. Remove the two TP sensor mounting screws, then pull the TP sensor out of the throttle body housing.
  4.  



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Fig. Remove the two attaching screws ...



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Fig. ... then remove the sensor from the throttle body by lifting straight up to disengage the throttle blade (arrow)

To install:

  1. Position the TP sensor against the throttle body housing, ensuring that the mounting screw holes are aligned. When positioning the TP sensor against the throttle body, slide the sensor straight onto the housing.
  2.  
  3. Install and tighten the sensor mounting screws until snug.
  4.  
  5. Attach the wiring harness connector to the sensor, then connect the negative battery cable.
  6.  

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the necessary air intake components to access the TPS.
  4.  
  5. Detach the electrical wire harness plug from the sensor.
  6.  
  7. Paint an alignment mark on the sensor housing to the throttle body.
  8.  
  9. Remove the sensor attaching bolts.
  10.  
  11. Remove the sensor from the throttle body.
  12.  
  13. Installation is the reverse of the removal procedure.
  14.  

Testing



  1. Disconnect the negative battery cable.
  2.  
  3. Disengage the wiring harness connector from the TP sensor.
  4.  
  5. Using a Digital Volt-Ohmmeter (DVOM) set on ohmmeter function, probe the terminals, which correspond to the Brown/White and the Gray/White connector wires, on the TP sensor. Do not measure the wiring harness connector terminals, rather the terminals on the sensor itself.
  6.  
  7. Slowly rotate the throttle shaft and monitor the ohmmeter for a continuous, steady change in resistance. Any sudden jumps, or irregularities (such as jumping back and forth) in resistance indicates a malfunctioning sensor.
  8.  
  9. Reconnect the negative battery cable.
  10.  
  11. Turn the DVOM to the voltmeter setting.
    WARNING
    Ensuring the DVOM is on the voltmeter function is vitally important, because if you measure circuit resistance (ohmmeter function) with the battery cable connected, your DVOM will be destroyed.

  12.  
  13. Detach the wiring harness connector from the PCM (located behind the lower right-hand kick panel in the passengers- compartment), then install a breakout box between the wiring harness connector and the PCM connector.
  14.  
  15. Turn the ignition switch ON and using the DVOM on voltmeter function, measure the voltage between terminals 89 and 90 of the breakout box. The specification is 0.9 volts.
  16.  
  17. If the voltage is outside the standard value or if it does not change smoothly, inspect the circuit wiring and/or replace the TP sensor.
  18.  

 
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