Cherokee, Grand Cherokee, 1999-2005

Throttle Position Sensor

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Operation



The 3 wire Throttle Position Sensor (TPS) is mounted on the throttle body and is connected to the throttle blade.

The TPS is a 3wire variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents the throttle blade position of the throttle body. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the resistance (output voltage) of the TPS changes.

The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. This will vary in an approximate range of from .26 volts at minimum throttle opening (idle), to 4.49 volts at wide-open throttle. Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.

The PCM needs to identify the actions and position of the throttle blade at all times. This information is needed to assist in performing the following calculations:



Ignition timing advance
 
Fuel injection pulse-width
 
Idle (learned value or minimum TPS)
 
Off-idle (0.06 volt)
 
Wide Open Throttle (WOT) open loop (2.608 volts above learned idle voltage)
 
Deceleration fuel lean out
 
Fuel cutoff during cranking at WOT (2.608 volts above learned idle voltage)
 
A/C WOT cutoff (certain automatic transmissions only)
 

Removal & Installation



3.7L & 4.0L
  1. Disconnect TPS electrical connector.
  2.  
  3. Remove TPS mounting screws.
  4.  
  5. Remove TPS.
  6.  

To Install:

The TPS is mounted to the throttle body. The throttle shaft end of throttle body slides into a socket in the TPS. The TPS must be installed so that it can be rotated a few degrees. (If sensor will not rotate, install sensor with throttle shaft on other side of socket tangs). The TPS will be under slight tension when rotated.

  1. Install TPS and retaining screws.
  2.  
  3. Tighten screws to 7 Nm (60 inch lbs.) torque.
  4.  
  5. Connect TPS electrical connector to TPS.
  6.  
  7. Manually operate throttle (by hand) to check for any TPS binding before starting engine.
  8.  

4.7L
  1. Remove air duct and air resonator box at throttle body.
  2.  
  3. Disconnect TPS electrical connector.
  4.  
  5. Remove two TPS mounting bolts (screws).
  6.  
  7. Remove TPS from throttle body.
  8.  

To Install:

The throttle shaft end of throttle body slides into a socket in TPS. The TPS must be installed so that it can be rotated a few degrees. If sensor will not rotate, install sensor with throttle shaft on other side of socket tangs. The TPS will be under slight tension when rotated.

  1. Install TPS and two retaining bolts.
  2.  
  3. Tighten bolts to 7 Nm (60 inch lbs.) torque.
  4.  
  5. Manually operate throttle control lever by hand to check for any binding of TPS.
  6.  
  7. Connect TPS electrical connector to TPS.
  8.  
  9. Install air duct/air box to throttle body.
  10.  

 
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