How To Test The MAP Sensor (2007-2010 2.2L Chevrolet Cobalt)

TEST 2: Verifying MAP Sensor Has 5 Volts And Ground

In certain cases the MAP sensor doesn't create a voltage signal that decreases/increases as you apply/release vacuum because it's missing either 5 Volts or Ground.

So in this test section, we're going to check that these 5 Volts and Ground are present.

The wire that supplies these 5 Volts is the gray (GRY) wire of the MAP sensor electrical connector. The GRY wire is identified with the number 3 in the photo above.

The wire that supplies Ground is the orange with black stripe (ORG/BLK) wire of the connector. The ORG/BLK wire is identified with the number 2 in the photo above.

IMPORTANT: The MAP sensor gets Ground directly from the fuel injection computer. For this reason you have to be very careful not to pass 12 Volts DC to this wire or you'll fry the fuel injection computer. The multimeter voltage test suggested in the test instructions is a safe way to test for this Ground.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Turn the key the ON position but don't start the engine.

3. 3

   Verify that the GRY wire has voltage (4.5 to 5 Volts DC) with the key on but engine off.
   
   Connect the red multimeter test lead (using the appropriate tool) to the GRY wire. Connect the black multimeter test lead to the negative battery terminal.
   
   Your multimeter should read 4.5 to 5 Volts DC.

4. 4

   Verify that the ORG/BLK wire has Ground with the key on but engine off.
   
   Connect the black multimeter test lead (using the appropriate tool) to the ORG/BLK wire. Connect the red multimeter test lead to the positive battery terminal.
   
   Your multimeter should read 12 Volts DC.

These are what the test results mean:

CASE 1: The multimeter confirms that the MAP sensor is being fed 5 Volts and Ground. This is the correct test result.

You can correctly conclude that the MAP sensor is defective if you have:

• Verified that its MAP voltage signal does not decrease/increase as you apply/release vacuum to the MAP sensor.
• Verified it's getting both 5 Volts and Ground.

Check my MAP sensor recommendations here: Where To Buy The MAP Sensor And Save.

CASE 2: Multimeter confirms that the MAP sensor IS NOT being fed 5 Volts. Without these 5 Volts the MAP sensor will not function.

Although it's beyond the scope of this tutorial to troubleshoot these missing 5 Volts, the most likely cause is an open-circuit problem in the wire between the MAP sensor's connector and the fuel injection computer's connector.

CASE 3: Multimeter confirms that the MAP sensor IS NOT being fed Ground. Without Ground the MAP sensor will not function.

Although it's beyond the scope of this tutorial to troubleshoot this missing Ground, the most likely cause is an open-circuit problem in the wire between the MAP sensor's connector and the fuel injection computer's connector.

More GM 2.2L Test Tutorials

If this tutorial was helpful, be sure and take a look at all of the 2.2L Chevrolet Cobalt test tutorials in this index: GM 2.2L Index Of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test The MAP Sensor (2005-2006 2.2L Chevrolet Cobalt).
• APP Sensor Tests (2005-2010 2.2L Chevrolet Cobalt And Pontiac G6).
• Electronic Throttle Body Tests (2005-2006 2.2L Chevrolet Cobalt).
• TAC System Wiring Diagram (2005-2009 2.2L Chevrolet Cobalt And Pontiac G5).