How To Test The Throttle Position Sensor (TPS) -1996, 1997, 1998, 1999 2.5L OHV Dodge Dakota

The throttle position sensor on the 1996, 1997, 1998, and 1999 2.5L OHV Dodge Dakota is probably one of the easiest components to test.

In this tutorial I will explain how to do the test all in plain English. The test results will help you confirm whether it is defective or not.

I'm also going to suggest where you can buy it and save a few bucks.

Also, you'll be able to troubleshoot the following diagnostic trouble codes:

  1. P0122: Throttle Position Sensor Circuit Low Input.
  2. P0123: Throttle Position Sensor Circuit High Input.
  3. P1121: Throttle Position Sensor Signal Lower Than Expected.
  4. P1122: Throttle Position Sensor Signal Higher Than Expected.

Contents of this tutorial:

  1. Basics Of The Throttle Position Sensor (TPS).
  2. TEST 1: Checking The Throttle Position Sensor (TPS) Signal.
  3. TEST 2: Making Sure The TPS Has Power and Ground.
  4. Where To Buy The TPS And Save.

NOTE: If you need to test the 1993-1995 2.5L Dakota TPS, you can find the tutorial here: How To Test The TPS (1993-1995 2.5L SOHC Dodge Dakota).

Basics Of The Throttle Position Sensor (TPS)

How To Test The Throttle Position Sensor (TPS) -1996, 1997, 1998, 1999 2.5L OHV Dodge Dakota

The throttle position sensor on your 2.5L OHV Dodge Dakota is a 3-wire component. To be able to diagnose it and find out if it's defective or not, we need to know what each one does.

In a nutshell, one wire feeds it with power. One wire feeds it with ground. And the other feeds the throttle position signal to your Dodge Dakota's fuel injection computer.

In the table below you'll find a brief description of each:

2.5L OHV Dodge Dakota TP Sensor Circuits
Pin Wire Color Description
1 VIO/WHT 5 Volts
2 ORG/DK BLU Throttle Position Signal
3 BLK/LT BLU Ground

TEST 1: Checking The Throttle Position Sensor (TPS) Signal

How To Test The Throttle Position Sensor (TPS) -1996, 1997, 1998, 1999 2.5L OHV Dodge Dakota

Be very first thing that we're gonna' do is to connect the multimeter to the throttle angle signal wire of the TPS. In a nutshell, the TP signal increases/decreases as we open/close the throttle plate.

The wire that we're gonna' test is the orange with dark blue stripe (ORG/DK BLU) wire of the TP sensor harness connector.

The TP sensor needs to remain connected to its connector, this means that you'll need to use a back probe or a wire piercing probe to access the signal (inside the wire). You can see example of a wire piercing probe here: Wire Piercing Probe.

Let me tell you right now that if he TP sensor is bad, it will usually stay stuck producing a specific voltage value. In other words, this value will not change when you open the throttle plate.

IMPORTANT: This is an on car test of the sensor and the throttle position sensor must remain connected to its harness connector.

These are the steps:

  1. 1

    Place your multimeter in Volts DC mode and connect the red test lead to the ORG/DK BLU wire of the TP sensor harness connector.

    NOTE: The TP sensor connector needs to be connected to the TPS, so you'll need to either back-probe the connector or use a wire piercing probe to get to the signal inside the wire (to see what a wire piercing probe looks like: Wire Piercing Probe Tool).

  2. 2

    Ground the black multimeter lead directly on the battery negative (-) post.

  3. 3

    Manually rotate the throttle.

    You'll get the best results by opening and closing the throttle directly on the throttle body instead of stepping on the accelerator pedal.

  4. 4

    The multimeter should show an increasing voltage as you (or your helper) open up the throttle.

    You'll get the best results by opening and closing the throttle directly on the throttle body instead of stepping on the accelerator pedal.

  5. 5

    The multimeter should show a decreasing voltage as you begin to close the throttle.

  6. 6

    Using a screwdriver's handle, gently tap the TP sensor as you open and close the throttle and observer the multimeter.

    The purpose (of tapping the TP sensor with the screwdriver's handle) is to see if the TP sensor shows gap's in the voltage signal. Why? Because a good TP sensor will show a continuous increasing or decreasing voltage signal even while getting tapped by the screw-driver's handle.

Let's analyze your test results:


CASE 1: The TP sensor signal's voltage increased and decreased smoothly and without gaps. This is the correct and expected TPS test result. This result tells you that the TPS, on your 2.5L OHV Dodge Dakota, is working correctly.

You can also conclude that the throttle position sensor is getting power and ground.

CASE 2: The TP sensor signal's voltage did not increase or decrease. This test result usually means that they TP sensor is defective but not always.

The next step, before we conclude that the TP sensor is bad, is to make sure that it's getting power and ground. For these two tests, go to: TEST 2: Checking Throttle Position Sensor (TPS) Power and Ground.

CASE 3: The TP sensor signal's voltage showed gaps in its voltage output as you tapped the sensor with the screwdriver. If the voltage signal (on your multimeter) reacted to the screwdriver tapping on the TP sensor, then this is a sure sign that the TPS is defective and needs to be replaced.