How To Test The MAP Sensor (2007-2008 3.5L Malibu)

TEST 2: Making Sure The MAP Sensor Is Getting Power

If you've reached this point, then your MAP sensor did not pass TEST 1.

There's a good chance that the MAP sensor isn't getting 5 Volts and thus the MAP signal voltage does not decrease/increase as you apply/release vacuum to it.

The wire that feeds power to the MAP sensor is the gray (GRY) wire of the 3-wire MAP sensor's electrical connector.

This power is in the form of 5 Volts DC. We'll be using our multimeter to check for the presence of these 5 Volts.

IMPORTANT: Avoid probing the front of the connector to test for these 5 Volts or you run the risk of damaging the female terminal within the connector. I recommend that you use a back-probe or a wire piercing probe to check for this voltage. You can see an example of this tool here: Wire Piercing Probe Review (Power Probe PWPPPPP01).

These are the test steps:

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 MAP sensor is getting power on the gray wire. This is the correct and expected test result.

The next step is to make sure that the MAP sensor is getting Ground. The wire that feeds your 3.5L Chevy Malibu MAP sensor with Ground is the orange with black 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. Without power, your 2007-2008 3.5L Chevy Malibu's MAP sensor is not going to work.

Although it's beyond the scope of this tutorial, your next step is to find out why this power is missing and restore it to the gray wire. Once power is restored, the MAP sensor will function again.

TEST 3: Making Sure The MAP Sensor Is Getting Ground

So far, your troubleshooting tests have confirmed that the MAP sensor signal is staying stuck at a specific voltage value while you apply/release vacuum. You've also made sure that the gray wire is feeding 5 Volts to the MAP sensor.

In this last test section, we're going to make sure that the orange with black stripe (ORG/BLK) wire is feeding Ground to the MAP sensor.

To check for this Ground, we're going to do a multimeter voltage test, similar to the one we did on the gray wire in previous test section.

IMPORTANT: The fuel injection computer of your 3.5L Chevy Malibu is the component that provides this Ground to the MAP sensor. For this reason you have to be very careful to not short this wire to battery 12 Volts (accidentally or intentionally) or you will fry the computer. The multimeter voltage test I'm suggesting in the test steps below is a safe way to check for this Ground.

Let's get testing:

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: The multimeter registered 10 to 12 Volts DC. This test result confirms that the orange with black stripe wire is feeding Ground to your 2007-2008 3.5L Chevy Malibu's MAP sensor.

With this test result you can conclude that the MAP sensor is defective only if it did not pass TEST 1 and it is getting 5 Volts on the gray wire.

CASE 2: The multimeter did not register 10 to 12 Volts DC. This test result tells you that the MAP sensor is not getting Ground. Without Ground it's not going to function.

Your next step is to find out why this Ground is missing. The most likely cause, of this missing Ground, is that the orange with black stripe wire is probably open between the MAP sensor connector and the PCM connector.

Although it's beyond the scope of this tutorial to check the continuity of the orange with black stripe wire, you have exonerated the MAP sensor itself as defective.

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