How To Test The EGR Valve (1996-1998 2.2L Chevrolet S10, GMC Sonoma)

TEST 2: EGR Pintle Position Sensor Performance Test

When the fuel injection computer commands the EGR valve's pintle to open and allow exhaust gas to recirculate into the intake manifold, the EGR pintle position sensor's output voltage increases.

When the computer commands the EGR valve to close (its pintle) and cut off exhaust gas into the intake manifold, the pintle position sensor's output voltage signal decreases.

Generally, when the pintle position sensor is bad, its output voltage value will stay stuck in one value as the pintle opens/closes.

You can easily verify that the pintle position signal increases/decreases with a multimeter and by physically pushing the pintle into the valve and releasing it.

CAUTION: The EGR valve has to be removed from the engine to perform this test. If the engine has been running for any length of time, let it cool down. The EGR valve can get very hot! Take all safety precautions to avoid burning your fingers or hands.

Let's get going:

  1. 1

    Remove the EGR valve from its place on the engine.

    IMPORTANT: Reconnect the EGR valve to its electrical connector if you had to disconnect it before continuing to the next step.

  2. 2

    Place your multimeter in DC Volts mode.

  3. 3

    Connect the red multimeter test lead to the wire that connects to the female terminal labeled with the letter C.

  4. 4

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

  5. 5

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

  6. 6

    Your multimeter should register 0.6 to 0.9 Volts DC at this point.

  7. 7

    With a small screw-driver push the EGR pintle up and into the EGR valve.

  8. 8

    The multimeter should display an increasing voltage reading as you push the EGR pintle up into the EGR valve.

    The maximum attainable voltage, with the EGR valve's pintle fully pressed into the EGR valve, will be about 4.5 Volts DC.

  9. 9

    Release the EGR valve's pintle back to its fully seated position.

  10. 10

    The voltage reading should return to the value you recorded in step 6.

  11. 11

    Repeat steps 7 thru 9 several times to make sure of your test result.

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

CASE 1: The voltage increased/decreased as you pushed/released the EGR pintle. This is the correct test result and tells you the EGR valve's pintle position sensor is working correctly.

You can also conclude that the EGR valve pintle position sensor is getting 5 Volts and Ground from the PCM.

The next step is to ensure that the EGR valve solenoid is getting Ground. Go to: TEST 5: Making Sure The EGR Solenoid Is Getting Ground.

CASE 2: The voltage DID NOT increase/decrease as you pushed/released the EGR pintle. It's not looking good for the EGR valve, but we still need to make sure the EGR valve pintle position sensor is getting 5 Volts and Ground.

For the first of the next two tests, go to: TEST 3: Making Sure The EGR Valve Pintle Position Sensor Is Receiving 5 Volts.

TEST 3: Making Sure The EGR Valve Pintle Position Sensor Is Receiving 5 Volts

Making Sure The EGR Valve Pintle Position Sensor Is Receiving 5 Volts. How To Test The EGR Valve (1998, 1999, 2000 2.2L Chevrolet S10, GMC Sonoma, And Isuzu Hombre)

In this test section, we'll make sure that the EGR valve's pintle position sensor is receiving 5 Volts.

The wire that delivers this voltage to the sensor is the gray (GRY) wire that connects to the terminal labeled with the letter D in the illustration above.

If the GRY wire delivers 5 Volts, your next step is ensuring the EGR valve's pintle position sensor is receiving Ground.

Let's get started:

  1. 1

    Place your multimeter in Volts DC mode.

  2. 2

    Disconnect the EGR valve from its pigtail connector.

  3. 3

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

  4. 4

    Gently probe the female terminal labeled with the letter D with the red multimeter test lead.

  5. 5

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

  6. 6

    The multimeter should read 4.5 to 5 Volts.

Let's interpret your test results:

CASE 1: The multimeter registered 5 Volts. This is the correct and expected test result.

Now that you've confirmed that the EGR valve is receiving 5 Volts, your next step is to see if its getting Ground. For this test, go to: TEST 4: Making Sure The EGR Valve Pintle Position Sensor Is Receiving Ground.

CASE 2: The multimeter DID NOT register 5 Volts. Without these 5 Volts, the EGR valve's pintle position sensor will not function.

Although it's beyond the scope of this tutorial, your next step is to find out why these 5 Volts are missing and restore them.

Chevrolet Vehicles:

  • S10 Pickup 2.2L
    • 1998, 1999, 2000

GMC Vehicles:

  • Sonoma 2.2L
    • 1998, 1999, 2000

Isuzu Vehicles:

  • Hombre 2.2L
    • 1998, 1999, 2000