Throttle Position Sensor

Replace the throttle position sensor (TPS) on the VP44 injection pump throttle body of the 5.9L Cummins diesel engine to restore proper throttle response and engine performance.

Warnings

Tools required

Parts

• Throttle Position Sensor (TPS) × 1 — Mopar 5269870AA or equivalent

Preparation

1. Park vehicle on level ground and set parking brake
2. Turn ignition off and remove key
3. Allow engine to cool to ambient temperature
4. Open hood and secure with prop rod
5. Disconnect negative battery cable to prevent electrical issues during sensor replacement

Procedure

1. 1

   Locate throttle position sensor
   On this Cummins diesel there is no throttle body or throttle-body-mounted TPS; throttle input is handled by an Accelerator Pedal Position Sensor (APPS), located either on the accelerator pedal assembly or on a bracket near the injection pump depending on year. Verify the specific sensor and its mounting location against a service manual for your exact model year before proceeding.
2. 2

   Disconnect TPS electrical connector
   Press down on the red locking tab on the TPS electrical connector and carefully pull the connector straight away from the sensor. Do not pull on the wires themselves. If connector is stuck, spray small amount of penetrating oil at base and wait 2-3 minutes.
3. 3

   Inspect connector and pins
   Examine the connector terminals for corrosion, bent pins, or moisture intrusion. Check the sensor pins for damage or corrosion. Clean connector with electrical contact cleaner if contamination is present and allow to dry completely.
4. 4

   Remove TPS mounting screws
   Remove the sensor mounting fasteners as specified in the service manual for your exact sensor; verify fastener type and count before beginning. These screws are small and can be tight, so use steady pressure to avoid stripping. Keep screws in a clean location for reinstallation if reusing.
   Torque spec

   TPS Screws3 Nm (2 lb-ft)
5. 5

   Remove old TPS
   Carefully pull the TPS straight away from the throttle body. The sensor shaft engages with the throttle shaft inside the body. Do not rotate or twist the sensor during removal as this may damage the throttle shaft. If sensor is stuck, gently wiggle while pulling straight out.
6. 6

   Inspect throttle shaft
   With TPS removed, visually inspect the exposed throttle shaft for wear, damage, or debris. The shaft should be clean and smooth with a flat or D-shaped profile. Wipe shaft clean with shop towel if any dirt or oil is present. Do not allow debris to enter the throttle body.
7. 7

   Prepare new TPS
   Remove new TPS from packaging and verify it matches the old unit in physical configuration and connector type. Check that the sensor shaft engagement feature (internal profile) is clean and free of debris. Apply a very light coating of dielectric grease to the electrical pins if desired for corrosion protection.
8. 8

   Install new TPS
   Align the new TPS shaft engagement feature with the throttle shaft, ensuring proper orientation. The sensor will only fit one way. Gently push the sensor straight onto the throttle body until it seats flush against the mounting surface. Do not force or rotate the sensor.
9. 9

   Install TPS mounting screws
   Start the sensor mounting fasteners by hand to ensure proper thread engagement. Tighten evenly to the torque value listed in the service manual for your exact sensor. Do not overtighten as this can crack the sensor housing.
   Torque spec

   TPS Screws3 Nm (2 lb-ft)
10. 10

    Reconnect electrical connector
    Align the TPS electrical connector with the sensor pins and push straight on until the red locking tab clicks into place. Tug gently on the connector to verify it is fully seated and locked. Ensure wiring harness has adequate slack and is not under tension.
11. 11

    Reconnect battery and clear codes
    Reconnect the negative battery cable and tighten securely. Turn ignition key to ON position (do not start engine). On 1996 and newer OBD2-equipped trucks, observe the dash MIL for normal bulb-check behavior; pre-1996 trucks do not monitor this circuit the same way. If any previous TPS-related codes were stored, they may need to be cleared with a scan tool.

Reassembly

1. No disassembly of other components is required for this procedure
2. Ensure all electrical connections are fully seated and locked
3. Verify TPS mounting screws are torqued to specification

Verification

• Start engine and verify it idles smoothly without surging or stalling
• Rev engine slowly and confirm smooth throttle response without hesitation
• Test drive vehicle and verify normal acceleration and no check engine light
• Use scan tool to verify TPS voltage changes smoothly from approximately 0.5V at idle to 4.5V at full throttle (if equipped with scan tool)
• Check for diagnostic trouble codes related to TPS circuit or rationality

Related trouble codes on this vehicle

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