How To Test The MAP Sensor (2000-2003 3.9L V6 Dodge Dakota)

TEST 2: Making Sure The MAP Sensor Has 5 Volts

If the MAP sensor doesn't get power (which is in the form of 5 Volts DC), it's not going to be able to create a decreasing voltage signal when vacuum is applied to it.

So in this test section we're going to make sure that the orange (ORG) wire is providing 5 Volts. These 5 Volts come from your Dodge Dakota's fuel injection computer.

We'll accomplish this test doing a simple multimeter voltage test on the ORG wire.

The ORG wire is labeled with the number 1 in the photo above.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAP sensor from its electrical connector.

3. 3

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

4. 4

   Connect the red multimeter test lead (using the appropriate tool) to the ORG wire.
   
   This is the wire labeled with the number 1 in the photo above.

5. 5

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

6. 6

   Your multimeter should read 4.5 to 5 Volts DC.

Let's analyze your test results:

CASE 1: 5 Volts are present in the ORG wire. This is the correct test result.

Now that you have confirmed that your Dodge Dakota's MAP sensor is getting 5 Volts, the next step is to make sure it's getting Ground. Go to: TEST 3: Making Sure The MAP Sensor Has Ground.

CASE 2: 5 Volts ARE NOT present on the ORG wire. Without these 5 Volts your Dodge Dakota's 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 ORG wire between the MAP sensor's connector and the fuel injection computer's connector.

TEST 3: Making Sure The MAP Sensor Has Ground

Up to this point you have confirmed that:

• The MAP sensor is not creating a decreasing voltage signal as vacuum is applied to it.
• The MAP sensor is getting 5 Volts on the ORG wire.

The MAP sensor also needs Ground to create a voltage signal. So in this test section we're going to make sure that the black with light blue stripe (BLK/LT BLU) wire is providing Ground from the fuel injection computer.

This test is also accomplished by doing a simple multimeter voltage test on the BLK/LT BLU wire.

The BLK/LT BLU wire is labeled with the number 3 in the photo above.

NOTE: Ground is provided by your 3.9L Dodge Dakota's fuel injection computer. So be careful and do not apply battery power (12 Volts DC) to the Ground wire or you'll fry the computer. The voltage test I'm describing below (to test for Ground) is a safe way of verifying the presence of this Ground.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAP sensor from its electrical connector.

3. 3

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

4. 4

   Connect the black multimeter test lead (using the appropriate tool) to the BLK/LT BLU wire.

5. 5

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

6. 6

   Your multimeter should read 10 to 12 Volts DC.

Let's analyze your test results:

CASE 1: Ground is present in the BLK/LT BLU wire. This is the correct test result.

The MAP sensor is defective and needs to be replaced if you have:

• Confirmed that its MAP voltage signal does not decrease/increase as you apply/release vacuum to the MAP sensor (TEST 1).
• Confirmed that the ORG wire is supplying 5 Volts DC (TEST 2).
• Confirmed that the BLK/LT BLU wire is supplying Ground (this test).

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

CASE 2: Ground is not present. 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 BLK/LT BLU wire between the MAP sensor's connector and the fuel injection computer's connector.

More 3.9L Dodge Dakota Tutorials

You can find a complete list of 3.9L V6 Dodge Dakota tutorials in this index:

• Chrysler 3.9L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test The Starter Motor (1991-1995 3.9L Dodge Dakota).
• How To Test Engine Compression (1993-2003 3.9L Dodge Dakota).
• How To Test For A Blown Head Gasket (1993-2003 3.9L Dodge Dakota).
• Engine Management Sensor Circuit Diagram (1994-1995 3.9L V6 Dodge Dakota).