How To Test The Throttle Position Sensor (2001-2004 2.0L Ford Escape)

Testing the throttle position sensor (TPS) on your 2.0L Ford Escape is easy to do with a simple multimeter.

In this tutorial, I'm going to show you step by step the three tests that will tell you if the sensor is good or bad.

These tests include checking the TPS signal voltage output and making sure the sensor is getting both power (VREF) and Ground (SIG RTN).

With your test results, you'll quickly know if the sensor is toast and needs to be replaced, or if it's good and the problem lies elsewhere.

You can find this tutorial in Spanish here: Cómo Probar El Sensor TPS (2.0L Ford Escape) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 2.0L Ford Escape: 2001, 2002, 2003, 2004.
• 2.0L Mazda Tribute: 2001, 2002, 2003, 2004.

Symptoms Of A Bad Throttle Position Sensor

The throttle position sensor (TPS) on your 2.0L Ford Escape is a critical engine management component. The PCM uses it to find out how much you're stepping on or letting off the accelerator pedal.

When TPS fails, you'll definitely see the check engine light illuminated and one or more of the following symptoms:

• A TPS diagnostic trouble code (DTC) stored in the PCM's memory:
  • P0121: Throttle Position (TP) Circuit Performance Problem.
  • P0122: Throttle Position (TP) Circuit Low Input.
  • P0123: Throttle Position (TP) Circuit High Input.
• Your 2.0L Ford Escape fails the smog check (state mandated emissions test).
• Bad gas mileage.
• Hard start and/or extended cranking time (after shut off).
• Black smoke coming out of the tailpipe.
• Hesitation when accelerating your vehicle down the road.

Thankfully, the TPS can be tested without a scan tool and in this tutorial, I'll show you how.

Where To Buy Your TP Sensor And Save

The following links will help you to comparison shop for the aftermarket and compare prices:

Not sure if the above TP sensor fits your particular 2.0L equipped Ford Escape? Don't worry, once you get to the site, they'll make sure it fits by asking you the particulars of your vehicle. If it doesn't fit, they'll find you the right one.

TEST 1: Testing The Throttle Position Sensor Voltage Signal

As you know, the TPS reports the throttle plate angle to the PCM as you step on or off the gas pedal, since the pedal is connected to the throttle plate by an accelerator cable.

To be more specific:

• When the throttle plate opens, the TPS signal voltage increases.
• When the throttle plate closes, the TPS signal drops back to its base voltage.

The first thing we'll do is tap into the gray with white stripe (GRY/WHT) wire of the TPS 3-wire connector with our multimeter and verify the TPS signal rises when the throttle plate opens and falls when it closes.

When the TPS fails, its signal voltage usually stays stuck at one value no matter how much you open or close the throttle plate.

NOTE: To check the TP signal voltage in the GRY/WHT wire, the sensor must stay connected to its connector. You'll need to either back probe the connector or use a wire-piercing probe on the signal wire to check the voltage. If you don't have one, this is the one I use and recommend without hesitation: Goupchn 4mm Banana to Banana Plug Test Leads Kit (Amazon affiliate link).

OK, let's start:

1. 1

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

2. 2

   Set your multimeter to DC Volts mode.

3. 3

   Turn the key to the ON position (engine OFF). Don't crank or start the engine.
   
   This step powers up the TPS.

4. 4

   Probe the middle wire of the TPS connector with the red multimeter test lead and an appropriate tool (like a back probe or a wire-piercing probe).
   
   The middle wire of the TPS connector should be a gray with white stripe (GRY/WHT) wire.
   
   NOTE: The TPS must stay connected to its 3-wire connector during this test.

5. 5

   With the throttle plate completely closed, the voltage should read between 0.3 and 0.9 Volts DC.
   
   This is your base reading.

6. 6

   Open the throttle plate slowly by hand. The voltage should climb smoothly as the plate opens.

7. 7

   At wide open throttle (WOT), the voltage should be between 3.5 and 4.5 Volts DC.

8. 8

   Close the throttle plate slowly. The voltage should fall back down to the same number you recorded in step 5.
   
   Verify that the closed-throttle reading matches your starting value.

9. 9

   Lightly tap the TPS body with the handle of a screwdriver while opening and closing the throttle plate.
   
   NOTE: Tapping on the sensor should not cause the readings to spike, cut out, or glitch. If it does, the TPS is faulty and must be replaced.

Let's take a look at your test results:

CASE 1: The TPS signal voltage rises and falls in sync with the throttle plate movement. This tells you the TP sensor on your 2.0L Ford Escape is doing its job. In other words, the sensor is tracking the plate correctly and isn't defective.

CASE 2: The throttle plate moves but the TPS signal voltage reading stays flat. This is usually tells you the TPS is toast.

Before you rush out for a replacement, you'll want to dig a little deeper. The next step is to confirm its receiving VREF power. Go to: TEST 2: Making Sure The TPS Is Getting Power (VREF).

CASE 3: The multimeter doesn't pick up any signal voltage at all. We can't call the TPS bad just yet.

A no voltage reading can also happen if the TP sensor isn't getting power or Ground in the first place. Our next step is to go to: TEST 2: Making Sure The TPS Is Getting Power (VREF).

TEST 2: Making Sure The TPS Is Getting Power (VREF)

If you've reached this point, the TPS signal voltage is either stuck at one value or completely missing (in TEST 1).

The next step is to make sure the brown with white stripe (BRN/WHT) wire is delivering 5 Volts to female terminal C.

If terminal C is has 5 Volts (with the key on engine off), we'll move on to TEST 3 and confirm the PCM is supplying Ground at terminal A of the connector.

Let's get testing:

1. 1

   Disconnect the TPS from its 3-wire connector.

2. 2

   Switch the key to the RUN position (ON) but don't crank or start the engine.

3. 3

   Set your multimeter to Volts DC mode.

4. 4

   Connect the black multimeter test lead to the battery's negative (-) post.

5. 5

   Gently probe the front of female terminal C with the red multimeter lead
   
   NOTE: Check that terminal C connects to the BRN/WHT wire of the connector.

6. 6

   The multimeter should show between 4.5 and 5.0 Volts DC.

Let's examine your test results:

CASE 1: Terminal C has 4.5 to 5 Volts. This means the throttle position sensor (TPS) is getting power from your 2.0L Ford Escape's PCM.

Now that you've confirmed the TPS is getting its VREF power, let's make sure its getting SIG RTN Ground (from the PCM too). For this test, go to: TEST 3: Making Sure The TPS Is Getting Ground (SIG RTN).

CASE 2: Terminal C DOES NOT have 4.5 to 5 Volts. Double-check all of your connections and repeat the test.

If you still don't see 4.5 to 5 Volts DC at terminal C, then the TPS itself is not at fault, since without power it won't function.

Although beyond the scope of this tutorial, your next step is to find out why this VREF power is missing and restore it to the BRN/WHT wire.

TEST 3: Making Sure The TPS Is Getting Ground (SIG RTN)

Your previous two tests have confirmed the following:

• The TPS signal voltage is stuck at one value regardless of throttle plate angle (TEST 1).
• The TPS is receiving its 5 Volts (VREF) supply (TEST 2).

For our last diagnostic test, we're going to make sure the orange (ORG) wire at terminal A is delivering Ground from your Ford Escape's PCM.

We'll check for its presence at terminal A with a multimeter voltage test, key on engine off (KOEO).

IMPORTANT: Ground comes directly from your Escape's PCM. Be careful —don't intentionally or accidentally connect this wire (circuit) to battery 12 Volts, or you'll deep-fry the powertrain control module (PCM).

Alright, let's get the ball rolling:

1. 1

   Disconnect the TPS from its 3-wire connector.

2. 2

   Switch the key to the RUN position (ON) but don't crank or start the engine.

3. 3

   Set your multimeter to Volts DC mode.

4. 4

   Connect the red multimeter test lead to the battery's positive (+) post.

5. 5

   Gently probe the front of female terminal A with the black multimeter lead
   
   NOTE: Check that terminal A connects to the ORG wire of the connector.

6. 6

   The multimeter should show between 10 to 12 Volts DC.

Now, let's see what your test result indicates:

CASE 1: The multimeter showed 10 to 12 Volts. This confirms that the TPS is getting the SIG RTN Ground from the PCM.

If you have confirmed the following, then you can conclude that the TPS is toast and needs to be replaced:

• The TPS signal voltage doesn't change with throttle plate angle (TEST 1).
• The TPS is getting 5 Volts from the brown white wire (TEST 2).
• In this test section, you've confirmed that the orange wire is delivering the SIG RTN Ground from the PCM.

When you're ready to replace it, here's the TPS I recommend:

• SCHNECKE 5S5127-AA Throttle Position TPS Sensor (Amazon affiliate link)

CASE 2: Multimeter DID NOT show 10 to 12 Volts. Double-check all of your connections and repeat the test.

If the SIG RTN Ground still isn't present terminal A, then the TPS itself is not at fault, since without this Ground it won't function.

Although beyond the scope of this tutorial, your next step is to find out why this SIG RTN Ground is missing and restore it to the ORG wire. The most likely cause is:

1. An open-circuit issue in the ORG wire between the TPS connector and the PCM.
2. The PCM has an internal problem (extremely rare, but it happens).

More 2.0L Ford Escape Diagnostic Tutorials

You can find a complete list of 2.0L Ford Escape (Mazda Tribute) tutorials in this index:

• 2.0L Ford Escape Index Of Articles.

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

• How To Test Engine Compression (2001-2004 2.0L Ford Escape).
• How To Test The Fuel Injectors (2001-2004 2.0L Ford Escape).
• Oxygen Sensor Heater Test -P0135 (2001-2004 2.0L Ford Escape).
• How To Test The Starter Motor (2001-2004 2.0L Ford Escape).