How To Test The Throttle Position Sensor (1998-2002 3.0L V6 Honda Accord)

The throttle position sensor on your 1998-2002 3.0L V6 equipped Honda Accord (Acura CL) can be accurately tested without a scan tool. How? By using a simple multimeter.

In this tutorial, I'll show you how in a step-by-step way so that you can conclude that the TPS is fried or is OK.

You can find this tutorial in Spanish here: Cómo Probar El Sensor TPS (1998-2002 3.0L Honda Accord) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 3.0L V6 Honda Accord: 1998, 1999, 2000, 2001, 2002, 2002.
• 3.0L V6 Acura CL: 1997, 1998, 1999.

Symptoms Of A Bad Throttle Position Sensor

The throttle position sensor's job is to tell your Accord's PCM how much the throttle plate opens/closes as you step on/step off the accelerator pedal to accelerate the engine/vehicle.

The PCM then uses this throttle plate angle info to inject more or less fuel (among several things). Being that this sensor is such a critical component of your Honda's engine management system, when it fails, you'll see one or more of the following symptoms:

1. Check engine light (CEL) is illuminated on your Accord's instrument panel.
2. A TPS diagnostic trouble code (DTC) stored in the PCM's memory:
   • P0120: Throttle Position Sensor Circuit Malfunction.
3. Bad gas mileage.
4. Hard start and/or extended cranking time (after shut off).
5. Black smoke coming out of the tailpipe.
6. Hesitation when accelerating your vehicle down the road.

Where To Buy Your TP Sensor And Save

Where can you buy the TP sensor for your 3.0L Honda Accord? 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:

Disclosure: As an Amazon Associate, I earn from qualifying purchases. Buying through these links helps support this site at no extra cost to you. I truly appreciate it!

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

In a nutshell, the TPS converts the throttle plate angle (as you step on/step off the accelerator) into an analog voltage signal.

Your 3.0L Accord's PCM then receives this throttle position signal on the red with black stripe (RED/BLK) wire that I've labeled with the number 2 in the photo above. It's the middle wire of the throttle position sensor's 3-wire connector.

This signal is very easy to measure with a simple multimeter. To be a bit more specific: what we'll do is see if the TPS creates an increasing voltage signal as we open the throttle plate to its Wide Open Throttle (WOT) position.

This TPS voltage signal should then decrease back to its original voltage when we slowly close the throttle plate (back to its closed position).

If you don't have a multimeter or need to upgrade yours, this is the one I use and recommend:

• Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (Amazon affiliate link)

NOTE: The throttle position sensor has to remain connected to its connector for this test to work (this is where a wire piercing probe comes in handy to get to the signal inside the wire. To see what one looks like, click here: Wire Piercing Probe Tool).

You can see this test step performed in this YouTube video: How To Test The TPS (1997, 1998, 1999, 2000, 2001 2.0L Honda CR-V) (NOTE: Although this video applies to the 1997-2001 2.0L Honda CR-V, the test procedure itself is the same for the 1998-2002 3.0L Honda Accord).

OK, let's start:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Connect the red multimeter test lead to the middle wire of the sensor's connector.
   
   This middle wire should a RED/BLK wire.

3. 3

   Ground the black multimeter test lead on the battery negative (-) terminal.

4. 4

   Have your helper turn the key to the ON position, but don't start the engine (this will power up the TP sensor).

5. 5

   Your multimeter should report a voltage between 0.2 to 0.9 Volts DC. If your multimeter doesn't, don't worry about it just yet, continue with the other steps.

PART 2:

1. 6

   Now, slowly open the throttle plate (by hand and from the engine compartment) while you observe the change in voltage numbers on your multimeter.
   
   For this test result to be accurate, you need to open the throttle plate by hand and not from inside the vehicle.

2. 7

   As the throttle plate opens, the voltage numbers will increase. This increase in voltage should be smooth and without any gaps or skips.
   
   Once the throttle is wide open, your multimeter should read somewhere between 3.5 to 4.5 Volts DC.

3. 8

   Now, slowly close the throttle.

4. 9

   As the throttle is closing, you should see the voltage decrease smoothly and without any gaps or skips, to the exact same voltage you noticed in step 5.

PART 3:

1. 10

   Lightly tap on the throttle position sensor with the handle of a screw-driver (or something similar, and I want to emphasize the words 'lightly tap') as you slowly open and close the throttle and observe the multimeter.
   
   If the TPS is bad, the tapping will cause the voltage numbers to skip or go blank. If the TPS is OK, the tapping will have no effect on the voltage numbers.

2. 11

   Repeat step 10 several times to make sure of your multimeter test results.

Let's take a look at your test results:

CASE 1: The voltage increased/decreased as you manually opened/closed the throttle plate. This means that your 3.0L equipped Honda's throttle position sensor is OK (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 3.0L Honda has a problem.

Before condemning the TPS to the scrap heap, you need to make sure that it's getting both power and Ground. To check for power, go to: TEST 2: Verifying Throttle Position Sensor Has Power.

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 power or Ground.

So the next step is to check that the TP sensor is getting power, go to: TEST 2: Verifying Throttle Position Sensor Has Power.

TEST 2: Verifying Throttle Position Sensor Has Power

If you've reached this point then you've confirmed that the TPS DID NOT pass TEST 1. In other words, it's not creating an increasing/decreasing throttle angle voltage signal.

To further confirm that the TPS is defective (or not), we need to make sure that it's getting power and Ground (since without these two, it won't produce a signal). So, in this test step, we're gonna' check that it's getting power.

This power is in the form of 5 Volts DC which are provided by your Honda's PCM thru' the yellow with blue stripe (YEL/BLU) wire that I've labeled with the number 3 in the photo above.

You can see this test step performed in this YouTube video: How To Test The TPS (1997, 1998, 1999, 2000, 2001 2.0L Honda CR-V) (NOTE: Although this video applies to the 1997-2001 2.0L Honda CR-V, the test procedure itself is the same for the 1998-2002 3.0L Honda Accord).

OK, let's get started:

1. 1

   Disconnect the TPS sensor from its electrical connector.

2. 2

   Place your multimeter's dial in Volts DC mode.

3. 3

   Turn the key the ON position but don't start the engine.
   
   This will power up the TP sensor's connector.

4. 4

   With the red multimeter test lead, gently probe the terminal that corresponds to the YEL/BLU wire of the TPS connector.
   
   IMPORTANT Be careful when probing the metal terminal of the TPS connector.

5. 5

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

6. 6

   Have your helper turn the key on but don't crank or start the engine.

7. 7

   Your multimeter should display 4.5 to 5 Volts on its screen.

Let's see what your test results mean:

CASE 1: Your multimeter registered 4.5 to 5 Volts. This is the correct test result and it confirms that the throttle position sensor (TPS) is getting power from the powertrain control module (PCM).

The next and last test, is to make sure that the throttle position sensor is getting Ground (from the PCM too). For this test, go to: TEST 3: Verifying The Throttle Position Sensor 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 your multimeter still doesn't register the 4.5 to 5 Volts DC then this test result tells you that the TPS itself is not at fault (and thus NOT causing the TPS trouble code).

Without power, the TPS can't create a throttle angle voltage signal. Although beyond the scope of this tutorial, your next step is to diagnose and restore this missing power.

TEST 3: Verifying The Throttle Position Sensor Has Ground

If you have reached this test step, you have confirmed that:

1. The TPS is not creating a throttle angle voltage signal that increases/decreases as you open/close the throttle plate (TEST 1).
2. The TPS is being fed power in the form of 4.5 - 5 Volts DC (TEST 2).

In this last test step, we'll see if the TPS is being fed Ground by the green with black stripe (GRN/BLK) wire that I've labeled with the number 1 in the photo above.

You can see this test step performed in this YouTube video: How To Test The TPS (1997, 1998, 1999, 2000, 2001 2.0L Honda CR-V) (NOTE: Although this video applies to the 1997-2001 2.0L Honda CR-V, the test procedure itself is the same for the 1998-2002 3.0L Honda Accord).

These are the steps:

1. 1

   Disconnect the TPS sensor from its electrical connector.

2. 2

   Place your multimeter's dial in Volts DC mode.

3. 4

   With the black multimeter test lead, gently probe the terminal that corresponds to the GRN/BLK wire of the TPS connector.
   
   NOTE: Be careful not to damage the terminal when probing the front of the connector.

4. 4

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

5. 5

   Turn the key On but don't start the engine. This will power up the PCM.

6. 6

   Your multimeter will display 10 to 12 Volts if the GRN/BLK wire is feeding the TPS with Ground.

Let's interpret your test results:

CASE 1: The multimeter showed 10 to 12 Volts. This is the correct test result and it tells you that the throttle position sensor, on your Honda, is being fed with Ground from the PCM.

You can conclude that the TPS sensor is bad if all three tests have confirmed that:

1. The TP sensor is not providing a varying voltage signal when manually opening the throttle plate.
2. The TP sensor is being fed 5 Volts DC.
3. The TP sensor is being fed Ground.

Replacing the TPS sensor will solve the TP sensor code lighting up the check engine light.

When you're ready to replace it, here two TP sensors from trusted automotive brands I personally use and recommend:

• Dorman 911-753 Throttle Position Sensor (Amazon affiliate link).
• APDTY 022864 Throttle Position Sensor (Amazon affiliate link).

CASE 2: The multimeter DID NOT show 10 to 12 Volts. Double check that you're testing the correct TP sensor harness terminal wire and repeat the test.

If your multimeter still doesn't indicate the presence of Ground in this terminal/wire, then you can conclude that there's an open in the wire between the TP sensor harness connector and the PCM's harness connector. In the extreme of cases, the PCM has an internal problem (although this is very rare).

Although testing these two conditions are beyond the scope of this article, you have now eliminated the throttle position sensor (TPS) on your 3.0L Honda as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).

More 3.0L V6 Honda Accord Diagnostic Tutorials

You can find a complete list of 3.0L V6 Honda Accord tutorials in this index:

• 3.0L V6 Honda Accord Index Of Articles.

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

• How To Test Engine Compression (1998-2007 3.0L V6 Honda Accord).
• How To Test The Starter Motor (1998-2003 3.0L V6 Honda Accord).
• How To Test A Misfire Condition And Misfire Codes (1998-2007 3.0L V6 Honda Accord).
• How To Troubleshoot A No Start (1998-2007 3.0L V6 Honda Accord).