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

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 labeled with the number 3.
   
   The terminal labeled with the number 3 connects 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: Be careful and do not short this wire to battery voltage, or you'll fry your Chrysler's PCM.

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 labeled with the number 1.
   
   The terminal labeled with the number 1 connects 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 Tutorials

I've written quite a few 3.9L V6 Dodge ‘how to’ tutorials that may help you troubleshoot the issues on your Dodge van, pick up or SUV. You can find all in these two indexes:

• 3.9L Dodge 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).