Chrysler RAM50/D50/Arrow 1979-1993 Repair Guide

Throttle Position Sensor

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OPERATION



See Figure 1

The Throttle Position Sensor (TPS), located at the entrance to the intake manifold plenum, sends voltage signals to the ECM depending on the position of the throttle. The electrical current the ECM sends into the TPS is monitored when it returns back to the ECM. Since the TPS is a resistor, the 5 volt current is changed depending on the TPS position. The further open the throttle is rotated, the greater the resistance in the TPS. Therefore, the more open the throttle, the less of the 5 volt current returns to the ECM.



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Fig. Fig. 1: The location of the TPS-all models are similar

The ECM can measure this voltage and knows how far open the throttle is. It uses this knowledge to help decide how to control the other MFI system components.

The signals of the TPS are more important for control of the automatic transmission than for control of the engine; shifting "impact shocks" are produced if there is a malfunction of the TPS.

If the voltage of the TPS deviates from the standard value, check once again after making the TPS adjustment. In addition, if there are any indications that the fixed Speed Adjusting Screw (SAS) has been moved, adjust the fixed SAS.

HARNESS TESTING



See Figures 2 and 3

The 1993, rear-wheel drive 2.4L (California) Pick-ups have the same engine controls as the 3.0L engines. All other 2.4L engines are listed as 2.4L engines.



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Fig. Fig. 2: The TPS harness testing procedure-2.4L engines



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Fig. Fig. 3: The TPS harness testing procedure-3.0L engines

  1. Unplug the harness connector from the TPS. Check for continuity of the ground circuit (terminal 4 on 2.4L engines, terminal 1 on 3.0L engine). If there is no continuity, repair or replace the harness between the following terminals:
    1. 2.4L engines: TPS terminal 4 and ECM terminals 14 and 24.
    2.  
    3. 3.0L engines: TPS terminal 1 and ECM terminals 17 and 24.
    4.  

  2.  
  3. Unplug the ECM harness connector and all other control module connectors which use TPS output. Check for an open or short-circuit between the TPS and the ECM. If a short or open-circuit is found, repair or replace the harnesses between the following terminals (use these terminals also for the initial test):
    1. 2.4L engines: TPS terminal 2 and ECM terminals 19.
    2.  
    3. 3.0L engines: TPS terminal 3 and 4 and ECM terminals 19 and 23, respectively.
    4.  

  4.  
  5. Unplug the harness connector from the TPS and turn the ignition switch to ON . Measure the power supply voltage of the TPS terminal 1 (2.4L) or terminal 4 (3.0L). If the voltage is not 4.8-5.2 volts, replace the ECM with a new unit.
  6.  

Before replacing the ECM or other computer module, either check or have the component in question checked.

COMPONENT TESTING



The 1993, rear-wheel drive 2.4L (California) Pick-ups have the same engine controls as the 3.0L engines. All other 2.4L engines are listed as 2.4L engines.

  1. Unplug the TPS harness connector.
  2.  
  3. Measure the resistance between terminals 1 and 4. The resistance should be between 3.5-6.5 kilohms.
  4.  
  5. Connect a pointer type ohmmeter between terminal 4 and 2 (2.4L) or terminal 1 and 3 (3.0L).
  6.  
  7. Operate the throttle valve slowly from the idle position to the full open position and check that the resistance changes smoothly in proportion with the throttle valve opening angle.
  8.  
  9. If the resistance fails to change smoothly, or is grossly out of specification, replace the TPS with a new unit.
  10.  

ADJUSTMENT



2.4L Engines

The 1993, rear-wheel drive 2.4L (California) Pick-ups have the same engine controls as the 3.0L engines. All other 2.4L engines are listed as 2.4L engines.

  1. Unplug the TPS harness connector and link the two unplugged connector halves using the test harness set (Dodge special tool).
  2.  
  3. Connect a voltmeter between terminal 2 and 4 of the TPS itself.
  4.  
  5. Turn the ignition switch ON and wait for 15 seconds or longer.
  6.  

When the ignition switch is turned ON, the idle speed control plunger extends to the fast idle opening angle. After 15 seconds has passed, the plunger contracts and stops at the initial position, which is the position corresponding to the idle position where the output voltage of the idle speed control motor position sensor is 0.9 volts.

  1. Check that the output voltage of the TPS is 0.48-0.52 volts.
  2.  
  3. If the voltage deviates from the standard value, loosen the TPS mounting bolts and turn the TPS body to adjust. Tighten the bolts securely after the adjustment.
  4.  

Turning the TPS body clockwise raises the output voltage. When the TPS is adjusted, there may be an output of diagnostic trouble code of idle speed control motor position sensor malfunction. This occurs when the TPS output voltage is outside the range of normal voltage at idling, and this is not a malfunction of the idle speed control motor position sensor.

  1. Turn the ignition OFF .
  2.  
  3. When the diagnostic trouble code is output during adjustment, erase the diagnostic trouble code by using a scan tool or disconnect the negative cable from the battery terminal for 10 seconds or more and then reconnect it. When the negative battery cable has been removed and installed again, idle the engine for approximately 15 minutes to warm it up. This will clear the memory of all diagnostic trouble codes output during the TPS adjustment.
  4.  

3.0L Engine See Figures 4 and 5

This procedure is also for the adjustment of the Closed Throttle Position (CTP) switch.

  1. Unplug the connector.
  2.  
  3. Use jumper wires to connect an ohmmeter between terminals 1 and 2 of the sensor/switch itself (not the harness connector).
  4.  
  5. Insert a feeler gauge with a thickness of 0.0256 in. (0.65mm) between the fixed SAS and the throttle lever.
  6.  
  7. Loosen the mounting bolts and turn the body fully clockwise.
  8.  
  9. In this condition, check for continuity between terminals 1 and 2.
  10.  
  11. Slowly turn the sensor/switch counter-clockwise until you find the point where there is no continuity between terminals 1 and 2. Tighten the mounting bolts to hold it in this position.
  12.  



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Fig. Fig. 4: Insert a feeler gauge between the fixed SAS and the throttle lever



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Fig. Fig. 5: After loosening the mounting bolts, the TPS can be rotated until the correct resistance is reached

  1. Link the sensor/switch and the harness connector with the test harness set (Dodge tool MB991348).
  2.  
  3. Connect a voltmeter between the sensor/switch terminal 3 and terminal 1.
  4.  
  5. Turn the ignition ON , but do not start the engine.
  6.  
  7. Check the TPS output voltage, which should be 400-1,000 mV.
  8.  
  9. If the voltage is outside the standard value, check the TPS and associated harness.
  10.  
  11. Remove the feeler gauge.
  12.  
  13. Turn the ignition switch to OFF.
  14.  

REMOVAL & INSTALLATION



2.4L Engines

See Figures 6, 7 and 8

  1. Disconnect the negative battery cable.
  2.  
  3. Remove any components obstructing access to the TPS.
  4.  
  5. Unplug the engine wiring harness connector from the sensor connector.
  6.  



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Fig. Fig. 6: Install the TPS as shown in this illustration-2.4L engines



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Fig. Fig. 7: Rotate the TPS 90° clockwise to set it-2.4L engines



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Fig. Fig. 8: The configuration of the TPS harness connector-2.4L engines

  1. Loosen and remove the two mounting screws, then extract the sensor from the throttle body.
  2.  

To install:
  1. Install the TPS to the throttle body as shown in the illustration.
  2.  
  3. Turn the TPS 90° in the clockwise direction to set it and tighten the screws.
  4.  
  5. Connect the circuit tester between terminal 4 (ground) and 2 (output), or between 2 (output) and 1 (power). Then, make sure that the resistance changes smoothly when the throttle valve is slowly moved to the wide open throttle position.
  6.  
  7. If the resistance does not change smoothly, adjust the TPS following the previously described procedures.
  8.  

3.0L Engines See Figures 9 and 10

  1. Disconnect the negative battery cable.
  2.  
  3. Remove any components obstructing access to the TPS.
  4.  
  5. Unplug the engine wiring harness connector from the sensor connector.
  6.  
  7. Loosen and remove the two mounting screws, then extract the sensor from the throttle body.
  8.  



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Fig. Fig. 9: Install the TPS as shown in the illustration-3.0L engines



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Fig. Fig. 10: Turn the TPS 90° counter-clockwise to set it-3.0L engines

To install:
  1. Install the TPS to the throttle body as shown in the illustration.
  2.  
  3. Turn the TPS 90° counter-clockwise to set it, and tighten the screws.
  4.  
  5. Connect the circuit tester between terminal 4 (ground) and 2 (output), or between 2 (output) and 1 (power). Then, make sure that the resistance changes smoothly when the throttle valve is slowly moved to the wide open throttle position.
  6.  
  7. Check for continuity across terminals 2 (closed throttle position switch) and 1 (ground) with the throttle valve both fully closed and fully open. With the throttle valve fully closed, there should be continuity, and when the throttle valve is fully open there should be no continuity. If there is no continuity with throttle valve fully closed, turn the TPS clockwise, and check again.
  8.  
  9. If the TPS does not conform to the above standards, this unit needs to be replaced with a new one.
  10.  

 
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