How To Test The TPS (1993-1996 5.2L Grand Cherokee)

TEST 2: Making Sure The TPS Has 5 Volts

If the TPS is not producing an increasing/decreasing voltage signal (in TEST 1), then there's a good chance that it might not be getting 5 Volts DC.

So in this test section we're going to make sure that the TPS is getting 5 Volts DC from the fuel injection computer.

On the 1993-1995 5.2L V8 Jeep Grand Cherokee, the wire that feeds the TPS with 5 Volts DC is a violet with white stripe (VIO/WHT) wire.

On the 1996 5.2L V8 Jeep Grand Cherokee, the wire that feeds 5 Volts to the TPS is a white with black stripe (WHT/BLK) wire.

To check for the presence of these 5 Volts we're going to 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 on but don't start the engine.

4. 4

   Connect the red multimeter test lead (using the appropriate tool) to the VIO/WHT (or WHT/BLK) 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 Jeep Grand Cherokee'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

So far, your throttle position sensor tests have confirmed that:

• The throttle position sensor is not creating a voltage signal that increases/decreases as you open/close the throttle plate.
• The throttle position sensor is getting 5 Volts DC from the fuel injection computer.

The last test that we need to do, before we condemn the TPS as bad, is to make sure that it's getting Ground.

The wire that supplies Ground to the TPS is the black with light blue stripe (BLK/LT BLU) wire of the sensor's 3-wire connector.

This wire is labeled with the number 3 in the photo above.

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 Jeep Grand Cherokee'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:

• 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 5.2L Jeep Grand Cherokee Tutorials

You can find a complete list of 5.2L Jeep Grand Cherokee tutorials in this index:

• Jeep 5.2L Index Of Articles.

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

• How To Do An Engine Compression Test (1993-1998 5.2L Jeep Grand Cherokee).
• How To Test A Blown Head Gasket (1993-1998 5.2L Grand Cherokee).
• How To Test The MAP Sensor (1993-1996 5.2L Grand Cherokee).
• Ignition System Wiring Diagram (1996-1998 5.2L Jeep Grand Cherokee).