How To Test The TPS (1992-1996 3.9L V6 Dodge Ram Pickup)

TEST 2: Making Sure The TPS Is Getting 5 Volts

So far your TPS tests have confirmed that:

• The TPS voltage signal does not increase/decrease as you open/close the throttle plate.

In this test section, we're gonna' make sure that the throttle position sensor (TPS) is getting power.

Power comes in the form of 5 Volts DC and they come from the fuel injection computer. The wire that delivers these 5 Volts is the VIO/WHT wire of the TPS connector.

Once we've confirmed that the sensor is receiving 5 Volts, then the next step is to make sure it's getting Ground (TEST 3).

NOTE: If you probe the front of the TPS harness connector (to test for these 5 Volts), do so in such a way that you do not damage the female terminal of the connector.

OK, these are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the throttle position sensor from its electrical connector.

3. 3

   Connect the black multimeter test lead directly on the battery's negative (-) terminal.

4. 4

   Turn the key to the ON position but don't crank or start the engine.

5. 5

   With the red multimeter test lead, gently probe the female terminal that connects to the wire labeled with the number 1.
   
   This terminal should connect to the VIO/WHT wire of the connector.
   
   NOTE: Depending on your specific vehicle, this wire may be a VIO/WHT wire or a VIO wire.

6. 6

   Your multimeter should register 4.5 to 5 Volts DC.

Let's examine your test results:

CASE 1: The VIO/WHT wire has power (4.5 to 5 Volts). This is the correct and expected test result.

Your next step is to make sure that the black with light blue stripe (BLK/LT BLU) wire is feeding Ground to the TPS. For this test, go to: TEST 3: Making Sure The TPS Is Getting Ground.

CASE 2: The VIO/WHT wire DOES NOT have power (4.5 to 5 Volts). Without 5 Volts the TPS will not produce a signal.

Although it's beyond the scope of this tutorial to find the reason why these 5 Volts are missing, you'll need to get yourself a wiring diagram (for your particular Dodge Ram pickup) and check the continuity of this wire between the TPS and the PCM.

TEST 3: Making Sure The TPS Is Getting Ground

Your TPS troubleshooting test results have confirmed that:

• One: The TP sensor IS NOT creating an increasing/decreasing throttle plate voltage signal on the ORG/DK BLU wire (TEST 1).
• Two: The VIO/WHT wire of the TPS harness connector is feeding the TP sensor with power (TEST 2).

The last test is to make sure that the BLK/LT BLU wire is feeding the TPS with Ground.

NOTE: The BLK/LT BLU wire connects directly to the fuel injection computer (PCM). Be careful and do not short this wire to battery voltage, or you'll fry your Dodge Ram pickup's PCM. The voltage test I'm describing below is a safe way to check for the presence of Ground in this circuit.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the throttle position sensor from its electrical connector.

3. 3

   Connect the red multimeter test lead directly on the battery's positive (+) terminal.

4. 4

   Turn the key to the ON position but don't crank or start the engine.

5. 5

   With the black multimeter test lead, gently probe the female terminal that connects to the wire labeled with the number 3.
   
   This terminal should connect to the BLK/LT BLU wire of the connector.

6. 6

   Your multimeter should register 10 to 12 Volts DC if Ground is present in the wire.

Let's take a look at what your test results mean:

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

You can conclude that the TPS is bad if you have:

1. Confirmed that the TPS is not creating a voltage signal that increases/decreases as you open/close the throttle plate (TEST 1).
2. Confirmed that the VIO/WHT wire is providing power (TEST 2).
3. Confirmed, in this test section, that the BLK/LT BLU wire is providing Ground.

If you'd like to save a few bucks on the TP sensor, check out the section: Where To Buy The TPS And Save.

CASE 2: Ground IS NOT present in the BLK/LT BLU wire. Without Ground the throttle position sensor will not produce a TPS signal.

Although it's beyond the scope of this tutorial to find the reason why this Ground is missing, you'll need to get yourself a wiring diagram (for your particular Chrysler) and check the continuity of this wire between the TPS and the PCM.

More 3.9L V6 Dodge Ram Pickup Tutorials

I've written quite a few 3.9L V6 Dodge 'how to' tutorials that may help you troubleshoot the issues on your Dodge pickup. You can find all in these two indexes:

• 3.9L V6 Dodge Ram Pickup Index Of Articles.
• 3.9L, 5.2L, 5.9L Dodge Index Of Articles.

Here's a small sample of the articles/tutorials you'll find in the indexes:

• How To Test A No Start Condition (Dodge 3.9L, 5.2L, 5.9L).
• How To Diagnose Misfire Codes (Dodge 3.9L, 5.2L, 5.9L).
• How To Test The Fuel Injectors (Dodge 3.9L, 5.2L, 5.9L).
• How To Test The Ignition Coil -No Start Tests (Chrysler 3.9L, 5.2L, 5.9L).
• How To Test The MAP Sensor (P0107, P0108) (Dodge 3.9L, 5.2L, 5.9L).