How To Test The MAF Sensor (2004-2008 3.5L Malibu)

TEST 2: Making Sure The MAF Sensor Is Getting Ground

So far, you've made sure that the MAF sensor is getting power. Now we're going to check that the black with white stripe (BLK/WHT) wire of the MAF sensor's electrical connector is providing Ground.

The black with white stripe (BLK/WHT) wire connects directly to the engine. Which makes this Ground available at all times.

In the photo above, the black with white stripe (BLK/WHT) wire is identified with the letter C.

To test for this Ground, we're gonna' do a simple multimeter voltage test.

IMPORTANT: Don't probe the front of the mass air flow sensor connector or you'll damage the connector and/or the female terminal inside of it. To check for Ground, you'll need to use a back probe or a wire piercing probe. You can see an example of this test tool here: Wire Piercing Probe Review (Power Probe PWPPPPP01).

Let's get started:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Connect the black multimeter test lead to the black with white stripe (BLK/WHT) wire identified with the letter C using an appropriate tool.

3. 3

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

4. 4

   The multimeter should register between 10 to 12 Volts DC.

Let's examine your test results:

CASE 1: The black with white stripe (BLK/WHT) wire is providing Ground. This is the correct and expected test result.

Now that you've checked the basics, our last test is to check the MAF sensor signal with a multimeter. For this test go to: TEST 3: Testing The MAF Signal With A Multimeter.

CASE 2: The black with white stripe wire does not have Ground. Without Ground, the mass air flow sensor (MAF) is not going to work.

The most likely cause of this missing Ground is in open in the black with white stripe (BLK/WHT) wire between the MAF sensor's connector and wherever it's connects to on the engine.

Repair the open in the black with white stripe wire to restore Ground to the mass airflow sensor. Once Ground is restored, the MAF sensor will function again.

TEST 3: Testing The MAF Signal With A Multimeter

If you've reached this point, you've made sure that the MAF sensor is getting both power and Ground in TEST 1 and TEST 2.

For our last test, we're going to check the MAF sensor signal itself with a multimeter. The multimeter has to have the ability to read Hertz (Hz) frequency.

What we're looking for, when testing the MAF signal, is for the signal to increase as you rev up the engine and then decrease as you release the throttle.

If the MAF sensor is defective, then it'll stay stuck producing a specific Hertz frequency number that will not increase/decrease as you rev up/rev down the engine.

NOTE: If you don't have a multimeter with Hertz function, check out my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing.

IMPORTANT: The mass airflow sensor must remain connected to its connector to test the MAF signal. To access the signal within the wire, you'll need to use a back probe on the connector or a wire piercing probe. You can see an example of this tool here: Wire Piercing Probe Review (Power Probe PWPPPPP01).

Let's get testing:

1. 1

   Place your multimeter in Hertz mode

2. 2

   Connect the red multimeter test lead to the yellow wire of the mass air flow sensor connector. This wire is labeled with the letter A in the photo above.
   
   IMPORTANT: The MAF sensor must remain connected to its electrical connector.

3. 3

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

4. 4

   Start the engine and let it warm up for 1 or 2 minutes.
   
   Note the Hertz reading on your multimeter while the engine is idling.
   
   It's normal for this reading to fluctuate a bit. But no matter the fluctuation, this will be your base reading.

5. 5

   Rev up the engine as you keep your eyes on the multimeter's frequency readings.
   
   The hertz frequency should increase as you rev up the engine.

6. 6

   Let go of the accelerator pedal and let the engine rev down.
   
   The Hertz reading on your multimeter should decrease as the engine revs down.

7. 7

   As you rev up/rev down the engine, the Hertz reading should increase/decrease.
   
   If the MAF sensor is defective, the Hertz value will stay stuck at one single number no matter how much you rev up the engine.

Let's examine your test results:

CASE 1: The Hertz signal increased/decreased as you revved up/revved down the engine. This is the correct and expected test result. Since you've made sure that the MAF sensor is getting power and Ground and it's creating its signal, you can conclude that it is functioning correctly.

CASE 2: The Hertz signal did not increase/decrease as you revved up/revved down the engine. This test result lets you know that the MAF sensor is defective only if you've made sure that it's getting power and Ground in TEST 1 and TEST 2.

More 3.5L V6 Chevy Malibu Tutorials

You can find a complete list of 3.5L V6 Chevy Malibu tutorials here: GM 3.5L V6 Index Of Articles.

Here's a list of articles, you'll find there:

• How To Test The Engine Compression (2004-2008 3.5L Chevrolet Malibu).
• How To Do A Cylinder Balance Test (2004-2008 3.5L Malibu).
• How To Test A Blown Head Gasket (2004-2008 3.5L Malibu).
• How Often Should I Replace The Spark Plugs (2004-2008 3.5L Malibu) .
• How To Test The MAP Sensor (2004-2006 3.5L Malibu).