How To Test The TPS (1997-2001 3.0L V6 Toyota Camry)

The throttle position sensor (TPS) on the 1997-2006 3.0L V6 Toyota Camry is a 3-wire sensor that can easily be tested with a multimeter.

That's right, you don't need a scan tool to be able to diagnose it as good or bad.

In this tutorial, I'll explain the three tests you can perform to find out if it's good or bad.

NOTE: This tutorial applies to the following vehicles:

• 3.0L Toyota Camry: 1997, 1998, 1999, 2000, 2001.
• 3.0L Toyota Avalon: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004.
• 3.0L Toyota Sienna: 1998, 1999, 2000, 2001, 2002, 2003.
• 3.0L Toyota Solara: 1999, 2000, 2001, 2002.

Symptoms Of A Bad Throttle Position Sensor

The throttle position sensor (TPS) is tasked with measuring the angle of the throttle plate inside the throttle body.

As you probably know, the throttle plate is linked to the accelerator pedal through an accelerator cable.

When you press the pedal, the throttle plate opens wider, allowing more air to enter the engine. Releasing the pedal causes the throttle plate to close, reducing the amount of air flowing in.

The fuel injection computer uses input from the TPS to track the throttle plate's position, making it an essential component of the fuel injection system.

If the TPS fails, it can lead to noticeable engine performance problems with your 3.0L V6 Toyota Camry. Some of the most common symptoms include:

• The check engine light (CEL) is illuminated on the instrument panel.
• A TPS diagnostic trouble code (DTC) is stored in the PCM's memory:
  • P0120: Throttle Position Sensor Circuit Malfunction.
  • P0121: Throttle Position Sensor Circuit Range/Performance Problem.
• Poor gas mileage.
• Hard starts or extended cranking time after shutting the engine off.
• Black smoke coming from the tailpipe.
• Hesitation when accelerating.

Circuit Descriptions Of The TPS

Camry TPS Pinout
Pin	Wire Color	Description
1	Blue (BLU)	TPS Signal
2	Brown (BRN)	Sensor Ground
3	Yellow (YEL)	5 Volts

To properly diagnose the throttle position sensor (TPS), it's important to understand how it functions. The TPS produces a voltage signal that changes in response to the movement of the throttle plate. This signal helps the fuel injection computer keep track of the throttle plate's position.

• When the throttle plate is fully closed, the TPS usually sends a voltage signal ranging between 0.5 and 0.9 Volts DC.
• As the throttle plate opens (for example, when you press the accelerator pedal), the voltage steadily increases. At full throttle, the signal typically reaches 4.5 to 5 Volts DC, depending on the specific vehicle.

When the TPS fails, a common issue is that the voltage signal gets "stuck" at one value, regardless of the throttle plate's movement.

This causes the TPS to send incorrect information to the fuel injection computer, leading to performance problems since the computer can no longer accurately monitor the throttle plate's position.

Where To Buy Your TP Sensor And Save

Where can you buy the TP sensor for your 3.0L Toyota Camry? You can buy it at your local auto parts store but it's gonna' cost a whole lot more. I suggest taking a look at the price of the TP sensor in the following links and compare:

Not sure if the above TP sensor fits your particular 3.0L Toyota Camry? 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

The first thing we're going to do is check if the TPS is creating a variable voltage signal.

Specifically, we need to verify that the TPS voltage signal increases as we open the throttle plate and decreases as we close it.

In most cases, a faulty throttle position sensor will produce a voltage signal that stays stuck at one value, regardless of whether the throttle plate is opening or closing.

To test this, we'll connect our multimeter to the blue (BLU) wire in the TPS's 3-wire connector. In the image above, this wire is labeled with the number 1.

IMPORTANT: For this test to work, the throttle position sensor must stay connected to its 3-wire connector. You'll need to use a back probe or a wire-piercing probe to access the TPS signal. You can see an example of this tool here (and where to buy it): Goupchn 4mm Banana to Banana Plug Test Leads Kit (Amazon affiliate link).

Let's get started:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Ground the black multimeter lead directly on the battery negative (-) post.

3. 3

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

4. 4

   Connect the red test lead to the BLU wire of the TP sensor's connector.

5. 5

   You should see a voltage between 0.4 to 0.9 Volts DC at this point (with the throttle plate closed).

6. 6

   Manually open the throttle plate.
   
   You'll get the best results by opening and closing the throttle plate directly on the throttle body instead of stepping on the accelerator pedal.

7. 7

   The multimeter should show an increasing voltage as you (or your helper) open up the throttle.
   
   At the wide open throttle plate position, you should see a voltage somewhere between 4.5 to 5 Volts DC.

8. 8

   Begin closing the throttle plate (slowly).
   
   Your multimeter should show a decreasing voltage. With the throttle plate fully closed, you should see the voltage you saw in STEP 5.

9. 9

   Using a screwdriver's handle, gently tap the TP sensor as you open and close the throttle plate and observe the multimeter.
   
   The purpose (of tapping the TP sensor with the screwdriver's handle) is to see if the TP sensor shows gaps (glitches) in the voltage signal. Why? Because a good TP sensor will show a continuous increasing or decreasing voltage signal even while getting tapped by the screw-driver's handle.

Let's examine your test results:

CASE 1: The voltage increased/decreased as you manually opened/closed the throttle plate. This test result confirms that the TP sensor is OK and not defective.

CASE 2: The voltage DID NOT increase/decrease as you manually opened/closed the throttle plate. This tells you that the throttle position sensor (TPS), on your Camry, has a problem.

Before condemning the TPS as bad, you need to make sure that it's getting both 5 Volts and Ground. For the next test, go to: TEST 2: Making Sure The TPS Has 5 Volts.

CASE 3: The multimeter DID NOT register any voltage. This test result doesn't condemn the TP sensor as bad just yet.

Why? Because the TP sensor may be missing either 5 Volts or Ground. So the next step is to check that the TP sensor is getting 5 Volts, go to: TEST 2: Making Sure The TPS Has 5 Volts.

TEST 2: Making Sure The TPS Has 5 Volts

If you've reached this point, you've confirmed that the throttle position sensor voltage signal does not increase or decrease as you open and close the throttle plate (TEST 1).

In this section, we're going to check if the yellow (YEL) wire is supplying the TPS with power (5 Volts DC). In the photo above, I've labeled the YEL wire with the number 3.

If the 5 Volts are present in the YEL wire, we'll proceed to the final test (TEST 3).

Here are the test steps:

1. 1

   Disconnect the TPS from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

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

4. 4

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

5. 5

   Probe the female terminal that connects to the YEL wire with the red multimeter test lead.

6. 6

   Your multimeter should read 4.5 to 5 Volts DC.

Let's examine your test results:

CASE 1: The multimeter registered 4.5 to 5 Volts. This is the correct test result and confirms that the throttle position sensor (TPS) is getting power from your Toyota Camry's fuel injection computer.

The next and last test, is to make sure that the throttle position sensor is getting Ground (from the fuel injection computer too). For this test, go to: TEST 3: Making Sure The TPS Has Ground.

CASE 2: Your multimeter DID NOT register 4.5 to 5 Volts. Double check all of your connections and repeat the test.

If the multimeter still doesn't register 4.5 to 5 Volts, this indicates that the TPS is not receiving power, meaning it's not the source of the problem. Without power, the TPS cannot produce a throttle angle voltage signal.

Although troubleshooting the missing 5 Volts goes beyond the scope of this tutorial, your next step would be to identify and resolve the issue causing the lack of power.

TEST 3: Making Sure The TPS Has Ground

So far, your test results have confirmed the following:

• The throttle position sensor is not producing a voltage signal that increases or decreases as you open and close the throttle plate (TEST 1).
• The throttle position sensor is receiving 5 Volts DC on the yellow (YEL) wire (TEST 2).

In this final test, we're going to check if the brown (BRN) wire of the TPS 3-wire connector is providing the sensor with Ground. In the photo above, I've labeled the BRN wire with the number 2.

This Ground is only present when the key is in the "ON" or "RUN" position and is supplied internally by the PCM (not a chassis Ground).

IMPORTANT: Be very careful not to accidentally or intentionally connect the Ground wire to battery voltage —this could damage the fuel injection computer on your 3.0L V6 Toyota Camry. The multimeter voltage test provided in the instructions is a safe and reliable way to check for Ground without risking any damage.

Let's get started:

1. 1

   Disconnect the TPS from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

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

4. 4

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

5. 5

   Probe the female terminal that connects to the BRN wire with the black multimeter test lead.

6. 6

   Your multimeter should read 10 to 12 Volts DC.

Let's interpret your test results:

CASE 1: The multimeter showed 10 to 12 Volts. This is the expected result and confirms that the throttle position sensor (TPS) on your 3.0L Toyota Camry is receiving Ground.

You can confidently determine that the TPS is faulty and needs replacement if the following have been verified:

• The TPS does not produce a voltage signal that changes as you open and close the throttle plate (TEST 1).
• The TPS is receiving 5 Volts DC on the yellow wire (TEST 2).
• The TPS is being supplied with Ground via the brown wire (this test).

CASE 2: Multimeter DID NOT show 10 to 12 Volts. First confirm that you're testing the correct wire and repeat the test. If the voltage is still missing, it means the TPS is not getting Ground.

Without Ground, the TPS cannot function, and the fuel injection computer will generate a TPS diagnostic trouble code (DTC), causing the check engine light (CEL) to turn on.

Diagnosing why Ground is missing goes beyond the scope of this tutorial, but at this point, you can rule out the TPS itself as the cause of the issue or the reason behind the DTC and check engine light.

More 3.0L Toyota Camry Tutorials

You can find a complete list of 3.0L Toyota Camry tutorials in this index:

• 3.0L Toyota Camry Index of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test Engine Compression (1992-2006 3.0L V6 Toyota Camry).
• How To Test For A Blown Head Gasket (1992-2006 3.0L V6 Toyota Camry).
• How To Test The MAF Sensor (1997-2001 3.0L V6 Toyota Camry).
• How To Test The Alternator (1997-2001 3.0L V6 Toyota Camry).