How To Test The Throttle Position Sensor (1991-1995 3.0L Chrysler, Dodge, Plymouth)

The throttle position sensor (TPS) provides one of the most crucial pieces of information your 1991-1995 3.0L V6 Chrysler, Dodge, or Plymouth vehicle needs to run correctly.

Fortunately, when it fails, it's not difficult to test. In this tutorial, I'll show you how to check that it's generating a TPS signal, receiving 5 Volts, and has a good Ground.

You'll also be able to diagnose any of the following OBD I TPS trouble codes that may be lighting up the check engine light:

• Trouble Code 24: TPS Voltage Low.
• Trouble Code 24: TPS Voltage High.

ES You can find this tutorial in Spanish here: Cómo Probar El Sensor TPS (1991-1995 3.0L Chrysler, Dodge, Plymouth) (at: autotecnico-online.com).

Basics Of The Throttle Position Sensor (TPS)

As you step on, or off, the accelerator, the throttle plate (on the intake manifold's throttle body) opens or closes.

This throttle plate action lets more (or less) air into the engine.

The throttle position sensor's job is to measure the throttle plate opens and closes and then relay this throttle plate angle info to your vehicle's fuel injection computer.

Once the fuel injection computer, receives this throttle plate angle information, it can inject the correct amount of fuel for the amount of air entering the engine.

As you're already aware, the throttle position sensor (TPS) has 3 wires coming out of its harness connector and the middle wire is the one that sends the TP signal back to the computer. The other two wires provide power and Ground (to the TPS).

In the table below, you'll find a short description of what each wire does:

Pin	Wire Color	Description
1	BLK/LT BLU	Sensor Ground
2	ORG/DK BLU (or DK BLU)	Throttle Position Signal
3	VIO/WHT (or VIO)	5 Volts

Where To Buy The TPS And Save

You can buy the throttle position sensor for your Chrysler in just about any auto parts store but you'll spend a whole lot more because they mark it up quite a bit.

My suggestion is to buy it online or at least comparison shop to get an idea of how much it costs and how much you can save.

The following links are for known automotive brand name throttle position sensors (avoid knock-off parts):

• Standard Motor Products TH70 Throttle Position Sensor (at: amazon.com).
• Walker Products 200-1010 Throttle Position Sensor (at: amazon.com).

TEST 1: Checking The Throttle Position Sensor (TPS) Signal

9 times out of 10, when the throttle position sensor fails, it simply stops creating a throttle plate signal.

To explain this a bit further: In a good throttle position sensor, as the throttle plate angle increases, the TP signal's voltage increases and as the throttle angle decreases, the TP signal's voltage decreases.

So, in this first test, we'll tap into the throttle position sensor's middle wire with a multimeter and see if the voltage signal increases when you open up the throttle plate and decreases when you close the throttle plate.

IMPORTANT: This is an on car test of the sensor and the throttle position sensor must remain connected to its harness connector. Also, depending on your specific vehicle, the middle wire of the TPS harness connector will be an ORG/DK BLU wire or a DK BLU wire.

Here are the test steps:

1. 1

   Set your multimeter to its DC Volts function.

2. 2

   Connect the black probe of the multimeter directly to the negative (-) terminal of the battery.

3. 3

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

4. 4

   Connect the red probe to the ORG/DK BLU or DK BLU wire of the TPS sensor connector.
   
   The ORG/DK BLU or DK BLU wire connects to the terminal labeled with the number 2 in the connector illustration above.
   
   NOTE: The TPS sensor should be connected to its connector, so you'll need to use a back probe on the backside of the connector or use a wire piercing probe to reach the signal within the wire. You can see an example of this tool and where to buy it here: Goupchn 4mm Banana to Banana Plug Test Leads Kit (Amazon affiliate link).

5. 5

   Your multimeter should read a voltage between 0.3 and 1.0 Volts DC with the throttle closed.

6. 6

   Manually open the throttle.
   
   NOTE: You'll get the best results by opening and closing the throttle directly at the throttle body instead of stepping on the gas pedal.

7. 7

   The multimeter should display a voltage that increases as you (or your helper) open the throttle.
   
   With the throttle fully open, your multimeter should read: 3.2 to 4.9 Volts DC.

8. 8

   Slowly close the throttle.

9. 9

   The multimeter should display a voltage that decreases as you start to close the throttle.

10. 10

    Using the handle of a screwdriver, lightly tap the TPS sensor while you open and close the throttle and watch the multimeter.
    
    The purpose (of tapping the TPS sensor with the screwdriver handle) is to see if the TPS sensor shows any gaps in the voltage signal. Why? Because a good TPS sensor will show a voltage signal that continually increases or decreases even as the screwdriver handle taps it.

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

CASE 1: The TP sensor signal's voltage increased and decreased smoothly and without gaps. This tells that the throttle position sensor on you car (or mini-van) IS NOT defective.

Since the throttle position sensor is creating an increasing/decreasing voltage signal on the ORG/DK BLU wire, this test result also says that:

1. The TPS is getting power on the VIO/WHT wire of its harness connector.
2. The TPS is getting Ground on the BLK/LT BLU wire of its harness connector.

CASE 2: The TP sensor signal's voltage did not increase or decrease. This test result usually means that the throttle position sensor on your car (or mini-van) is bad and needs to be replaced.

To make sure it's defective, I suggest that you verify that it's getting power and Ground. So, to continue with the TPS diagnostic, go to: TEST 2: Making Sure The TPS Is Getting Power.

CASE 3: The TP sensor signal's voltage showed gaps in its voltage output as you tapped the sensor with the screwdriver. If the gaps in the multimeter's voltage readings only showed up when you were tapping on the TPS (with the screwdriver's handle) then this test result tells you that the TPS is bad and needs to be replaced.

TEST 2: Making Sure The TPS Is Getting Power

In this test step, we're gonna check that the violet with white stripe (VIO/WHT) wire of the TP sensor's 3-wire connector has power with a simple multimeter voltage test.

If the TP sensor is getting power (5 Volts DC), then your next and last test step is to confirm that the TPS is also getting Ground.

OK, let's get started:

1. 1

   Set your multimeter to Volts DC mode.

2. 2

   Disconnect the TPS sensor from its electrical connector.

3. 3

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

4. 4

   Ask your helper to turn the key to the RUN position, but do not crank or start the engine.

5. 5

   Gently probe the terminal labeled with the number 3 with the red multimeter test lead.
   
   The female terminal marked with the number 3 should connect to the VIO/WHT wire in the TPS sensor connector.
   
   NOTE: Be careful not to damage the female terminal with the multimeter probe, or you'll need to replace the connector.

6. 6

   Your multimeter should read from 4.5 to 5 Volts DC if the VIO/WHT wire is supplying 5 Volts to the TPS sensor.

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

CASE 1: The multimeter registered 4.5 to 5 Volts DC. This is the correct and expected test result and tells you that the throttle position sensor (TPS) is getting power.

Your next step is to make sure that the TPS is getting Ground on the BLK/LT BLU wire. For this test, go to: TEST 3: Making Sure The TPS Is Getting Ground.

CASE 2: The multimeter DID NOT register 4.5 to 5 Volts DC. Re-check your multimeter test lead connections and re-test.

If the multimeter still indicates the TPS is not getting power, then you've found the reason why the TPS did not create a voltage signal in TEST 1.

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 Chrysler car or mini-van) and check the continuity of this wire between the TPS and the PCM.

TEST 3: Making Sure The TPS Is Getting Ground

So far, you have checked and confirmed that your car or mini-van's throttle position sensor is:

• Not creating an increasing/decreasing voltage signal on the ORG/DK BLU wire (TEST 1).
• Is getting power on the VIO/WHT wire (TEST 2).

The last test is to make sure that the black with light blue stripe (BLK/LT BLU) wire is feeding the TPS with Ground.

CAUTION: Be careful and make sure not to short the BLK/LT BLU wire to battery voltage; otherwise, you risk damaging your Stratus' fuel injection computer, which is a headache (and a costly mistake) you'll want to avoid. The multimeter voltage test I'm suggesting below is a safe way to check for the presence of Ground in this wire.

These are the test steps:

1. 1

   Set your multimeter to Volts DC mode.

2. 2

   Disconnect the TPS sensor from its electrical connector.

3. 3

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

4. 4

   Ask your helper to turn the key to the RUN position, but do not crank or start the engine.

5. 5

   Gently probe the terminal labeled with the number 1 with the black multimeter test lead.
   
   The female terminal marked with the number 1 should connect to the BLK/LT BLU wire in the TPS sensor connector.
   
   NOTE: Be careful not to damage the female terminal with the multimeter probe, or you'll need to replace the connector.

6. 6

   Your multimeter should read from 10 to 12 Volts DC if the BLK/LT BLU wire is supplying Ground to the TPS sensor.

Let's examine your multimeter test results:

CASE 1: The multimeter registered 10 to 12 Volts DC. This test result confirms that the TPS is getting Ground.

You can conclude that the TPS sensor is bad and needs to be replaced if you have:

• Confirmed the sensor is not creating a voltage signal that increases/decreases (TEST 1).
• Confirmed it's getting power (TEST 2).
• Confirmed it's getting Ground (this test section).

Ready to buy the TPS sensor? These are the known automotive brand names I use, trust, and recommend:

• Standard Motor Products TH70 Throttle Position Sensor (Amazon affiliate link).
• Walker Products 200-1010 Throttle Position Sensor (Amazon affiliate link).

CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Re-check all of your test connections and repeat the test.

If the multimeter still does not show the indicated voltage, then you've found the reason why the TPS did not create a voltage signal in TEST 1.

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 3.0L Chrysler Tutorials

You can find a complete list of tutorials in this index: Chrysler 3.0L Index Of Articles.

• How To Replace The Distributor (1988-2000 3.0L Chrysler).
• How To Test Engine Compression (1987-2000 3.0L Chrysler).
• How To Test The MAP Sensor (1991-1995 3.0L Chrysler).
• How To Test For A Broken Timing Belt (1998-2000 3.0L SOHC Chrysler).
• Ignition Distributor System Tests 3.0L Chrysler, Dodge, Plymouth (at: easyautodiagnostics.com).