How To Test The Throttle Position Sensor (3.0L Honda)

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 wire that connects to terminal #3 of the TPS connector (see illustration 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

   Check the TPS connector terminal that corresponds to pin #3, of the TPS connector, with the red multimeter test lead.
   
   IMPORTANT Be careful when probing the metal terminal of the TPS connector. Damaging the terminal will require that you replace the connector. Use a back probe or a wire piercing probe instead of probing the front of the 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

In this last test step, we'll see if the TPS is being fed Ground by the wire that connects to terminal #1 of the TPS connector.

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).

If in this test section you confirm that the TPS is being fed with Ground by the PCM, then you can conclude the TPS has failed and needs to be replaced.

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. 3

   Probe the TPS connector wire that connects to the TP sensor's pin #1 with the black multimeter test lead..
   
   Be careful not to damage the terminal if you probe it on the front of the connector. If possible, you should use a back probe or a wire-piercing probe to check this circuit.

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 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.

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 Honda 3.0L Tutorials

The following tutorials may be of help/interest:

• How To Test The Coil on Plug Ignition Coil (Honda 3.0L).
• How To Test For A Broken Timing Belt (Honda 3.0L) (at: troubleshootmyvehicle.com).
• How To Troubleshoot A No Start (Honda 3.0L) (at: troubleshootmyvehicle.com).
• How To Test A Misfire Condition and Misfire Codes (Honda 3.0L) (at: troubleshootmyvehicle.com).