TEST 2: Making Sure The TPS Has 5 Volts

Making Sure The TPS Has 5 Volts. How To Test The TPS (1990, 1991 5.2L V8 Dodge Dakota)

In this test section we're going to make sure that the throttle position sensor is getting power from the fuel injection computer.

Power is in the form of 5 Volts DC and are delivered to the throttle position sensor by the violet with white stripe (VIO/WHT) wire.

The VIO/WHT wire connects to the female terminal labeled with the number 3 in the photo above.

If 5 Volts are present in the violet with white stripe (VIO/WHT) wire then our next step is to make sure that the throttle position sensor is getting Ground.

These are the test steps:

  1. 1

    Place your multimeter in Volts DC mode.

  2. 2

    Disconnect the TPS from its electrical connector.

  3. 3

    Turn the key on but don't start the engine.

  4. 4

    Connect the red multimeter test lead (using the appropriate tool) to the VIO/WHT wire.

  5. 5

    Connect the black multimeter test lead to the negative (-) battery terminal.

  6. 6

    Your multimeter should read 4.5 to 5 Volts DC.

Let's analyze your test results:

CASE 1: The VIO/WHT wire has 5 Volts present. This is the correct test result.

Now that you have confirmed that your Dodge Dakota's TPS is getting 5 Volts, the next step is to make sure it's getting Ground. Go to: TEST 3: Making Sure The TPS Has Ground.

CASE 2: The VIO/WHT wire DOES NOT have 5 Volts present. Without these 5 Volts the TPS will not function.

Although it's beyond the scope of this tutorial to troubleshoot these missing 5 Volts, the most likely cause is an open-circuit problem in the violet with white stripe (VIO/WHT) wire between the TPS sensor's connector and the fuel injection computer's connector.

TEST 3: Making Sure The TPS Has Ground

Making Sure The TPS Has Ground. How To Test The TPS (1990, 1991 5.2L V8 Dodge Dakota)

If you've reached this point your test results have confirmed that:

  1. The TPS voltage signal does not increase/decrease as you open/close the throttle plate (TEST 1).
  2. 5 Volts DC are present on the violet with white stripe (VIO/WHT) wire (TEST 2).

The last thing that we need to do, is to make sure that the throttle position sensor is getting Ground.

Ground is provided by the black with light blue stripe (BLK/LT BLU) wire of the 3-wire connector.

We can verify the presence of Ground, in the black with light blue stripe (BLK/LT BLU) wire with a simple multimeter voltage test.

NOTE: Ground is provided by your 5.2L Dodge Dakota's fuel injection computer. So be careful and do not apply battery power (12 Volts DC) to the Ground wire or you'll fry the computer. The voltage test I'm describing below (to test for Ground) is a safe way of verifying the presence of this Ground.

These are the test steps:

  1. 1

    Place your multimeter in Volts DC mode.

  2. 2

    Disconnect the TPS from its electrical connector.

  3. 3

    Turn the key on but don't start the engine.

  4. 4

    Connect the black multimeter test lead (using the appropriate tool) to the BLK/LT BLU wire.

  5. 5

    Connect the red multimeter test lead to the positive (+) battery terminal.

  6. 6

    Your multimeter should read 10 to 12 Volts DC.

Let's analyze your test results:

CASE 1: Ground is present in the BLK/LT BLU wire. This is the correct test result.

You can correctly conclude that the TPS is defective if you have:

  1. Confirmed that the TPS voltage signal does not increase/decrease as you opened/closed the throttle plate (TEST 1).
  2. Confirmed that the TPS is getting 5 Volts on the VIO/WHT wire (TEST 2).
  3. Confirmed that the TPS is getting Ground on the BLK/LT BLU wire (this test).

Check my TPS recommendations here: Where To Buy The TPS And Save.

CASE 2: Ground is not present in the BLK/LT BLU wire. Without Ground the TPS will not function.

Although it's beyond the scope of this tutorial to troubleshoot this missing Ground, the most likely cause is an open-circuit problem in the BLK/LT BLU wire between the throttle position sensor's connector and the fuel injection computer's connector.

Where To Buy The TPS And Save

The throttle position sensor is usually not an expensive engine management component. The following links will help you to comparison shop and hopefully save you a few bucks on the 1990-1991 5.2L V8 Dodge Dakota's TPS:

NOTE: The above throttle position sensor (TPS) fits the following vehicles: 1990, 1991 5.2L V8 Dodge Dakota.

More 5.2L Dodge Dakota Tutorials

You can find a complete list of 5.2L Dodge Dakota tutorials in this index:

  1. Chrysler 5.2L, 5.9L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

  1. Blown Head Gasket Tests (1997-1999 V8 Dodge Dakota, Durango).
  2. How To Test The Fuel Pump (1997-1999 V8 Dodge Dakota, Durango).
  3. How To Test The Crankshaft Position Sensor (1997-1999 V8 Dakota, Durango).
  4. How To Test The Throttle Position Sensor (1997-1999 V8 Dakota, Durango).
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