How To Test The MAP Sensor (2004-2006 3.5L Malibu)

TEST 2: Making Sure The MAP Sensor Is Getting Power

If in TEST 1 the MAP sensor's voltage signal did not decrease/increase or simply showed a 0 voltage, then there's a good chance that the MAP sensor isn't getting power.

So in this test action we're gonna' make sure that the gray (GRY) wire of the MAP sensor's electrical connector has 4.5 to 5 Volts DC when we turn the key on.

IMPORTANT: Avoid probing the front of the connector or you risk damaging its female terminals. You should use a back probe instead 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

   Disconnect the MAP sensor from its connector and place your multimeter in Volts DC mode.

2. 2

   With the red multimeter test lead probe the gray (GRY) wire of the MAP sensor's electrical connector.
   
   IMPORTANT: Avoid probing the front of the MAP sensor's connector.

3. 3

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

4. 4

   Turn the key on but don't crank or start the engine.

5. 5

   Your multimeter should read 4.5 to 5 Volts DC.

Let's examine your test results:

CASE 1: The gray (GRY) wire of the MAP sensor has 5 Volts DC with the key on. This is the correct and expected test result.

Now that you have confirmed that the gray (GRY) wire is feeding power to the MAP sensor, the next test is to make sure that the MAP sensor is getting Ground on the orange with black (ORG/BLK) stripe wire. For this test go to: TEST 3: Making Sure The MAP Sensor Is Getting Ground.

CASE 2: The gray wire does not have 5 Volts with the key on. Without power, your 3.5L Chevy Malibu's MAP sensor will not work.

The most likely cause of this missing voltage is and open in the gray (GRY) wire between the MAP sensor connector and your Chevy Malibu's fuel injection computer.

Your next step is to check the continuity of the gray (GRY) wire between the MAP sensor connector and the fuel injection computer connector. If the wire is open, repair the open to restore power to the MAP sensor.

TEST 3: Making Sure The MAP Sensor Is Getting Ground

So far you have confirmed that the MAP sensor isn't creating an increasing/decreasing voltage signal and that it is getting power from the gray (GRY) wire of its connector.

For our last test we're going to make sure that the orange with black stripe (ORG/BLK) wire of the MAP sensor's electrical connector is feeding it with Ground.

This Ground is provided by your 3.5L Chevy Malibu fuel injection computer.

To make sure that this Ground is present, we're going to do a multimeter voltage test very much like the one we did in TEST 2.

IMPORTANT: Be careful and do not short the orange with black stripe (ORG/BLK) wire to battery voltage or you will fry your Chevy Malibu's fuel injection computer. The voltage test I'm suggesting in the test instructions is a safe way to test this Ground circuit.

These are the test steps:

1. 1

   Disconnect the MAP sensor from its electrical connector and place your multimeter in Volts DC mode.

2. 2

   Probe the orange with black stripe (ORG/BLK) wire with the black multimeter test lead.

3. 3

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

4. 4

   Turn the key on but don't crank or start the engine.

5. 5

   Your multimeter should read 10 to 12 Volts DC.

Let's examine your test results:

CASE 1: Your multimeter registered 10 to 12 Volts. This test result confirms that the orange with black stripe (ORG/BLK) wire is providing Ground from the PCM to your 3.5L Chevy Malibu's MAP sensor.

You can conclude that your Chevy Malibu's MAP sensor is defective if you have confirmed in TEST 1 that the voltage signal does not increase/decrease when you applied/released vacuum and you have confirmed that the MAP sensor is getting power in TEST 2.

CASE 2: Your multimeter did not register 10 to 12 Volts DC. Without Ground, your Chevy Malibu's MAP sensor will not function.

The most likely cause of this missing Ground is an open in the orange with black stripe (ORG/BLK) wire between the MAP sensor connector and your Chevy Malibu fuel injection computer.

Your next step is to check the continuity of the orange with black stripe wire between the MAP sensor connector and the fuel injection computer's connector. If the wire is open, repair the open to restore Ground to the MAP sensor.

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 Often Should I Replace The Spark Plugs (2004-2008 3.5L Malibu).
• How To Test A Blown Head Gasket (2004-2008 3.5L Malibu).
• How To Test The MAF Sensor (2004-2008 3.5L Malibu).