How To Test The Throttle Position Sensor (1992-1996 3.9L Dodge Dakota)

TEST 2: Making Sure The TPS Has 5 Volts

If the throttle position sensor, on your 1992-1996 3.9L Dodge Dakota, did not pass TEST 1, then there's a chance that it might not be receiving 5 Volts from the violet with white stripe (VIO/WHT) wire of its electrical connector.

So in this test section, we're gonna' make that these 5 Volts are present with the key on but engine off.

If these 5 Volts are present, then the next (and last) test is to make sure that the black with light blue stripe (BLK/LT BLU) wire is feeding the throttle position sensor with Ground.

To check for the presence of the 5 Volts we're gonna' do a simple multimeter voltage test.

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 the ON position 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: 5 Volts are 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: 5 Volts are not 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

So far your tests have confirmed that:

• The TPS is not creating an increasing/decreasing voltage signal as the throttle plate is opened/closed (TEST 1).
• The TPS is getting 5 Volts on the violet with white stripe (VIO/WHT) wire.

In this last test we're gonna' make sure that the black with light blue stripe (BLK/LT BLU) wire is feeding the TPS with Ground.

To check for the presence of Ground, in the black with light blue stripe (BLK/LT BLU) wire, we're gonna' do a simple multimeter voltage test.

NOTE: Ground is provided by your 3.9L 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 the ON position 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:

• Confirmed that the TPS voltage signal does not increase/decrease as you opened/closed the throttle plate (TEST 1).
• Confirmed that the TPS is getting 5 Volts on the VIO/WHT wire (TEST 2).
• 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.

More 3.9L Dodge Dakota Tutorials

You can find a complete list of 3.9L V6 Dodge Dakota tutorials in this index:

• Chrysler 3.9L Index Of Articles.

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

• How To Test The Starter Motor (1991-1995 3.9L Dodge Dakota).
• How To Test Engine Compression (1993-2003 3.9L Dodge Dakota).
• How To Test For A Blown Head Gasket (1993-2003 3.9L Dodge Dakota).
• Engine Management Sensor Circuit Diagram (1994-1995 3.9L V6 Dodge Dakota).