How To Test The MAP Sensor (1991-1995 2.5L Caravan, Voyager)

TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts

In this test section we'll gonna' make sure that the manifold absolute pressure (MAP) sensor is receiving 5 Volts, since without them it won't function.

The wire that carries these 5 Volts from the fuel injection to the MAP sensor is the violet with white stripe (VIO/WHT) wire of the connector.

In my photo of the connector above, this wire is labeled with the number 1.

NOTE: Avoid probing the front of the female terminal to test for these 5 Volts or you could permanently damage the female terminal. Instead, you should back-probe the connector with the appropriate tool or use a wire-piercing probe.

OK, let's get started:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAP sensor from its electrical connector.

3. 3

   Connect the red multimeter test lead to the VIO/WHT wire of the MAP sensor harness connector
   
   This is the wire that connects to the terminal labeled with the number 1 in the photo above.

4. 4

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

5. 5

   Have a helper turn the key to the On position, but don't crank or start the engine after the multimeter test leads have been set up.

6. 6

   Your multimeter should register 4.5 to 5 Volts DC if the VIO/WHT wire is feeding the manifold absolute pressure (MAP) sensor with power.

Let's take a look at what your test results mean:

CASE 1: The VIO/WHT wire has 4.5 to 5 Volts present. This is the correct and expected test result and lets you know that the manifold absolute pressure (MAP) sensor is getting the power it needs to function.

Now, we need to make sure that the MAP sensor is receiving Ground. The wire that feeds the MAP sensor with Ground is the black with light blue stripe (BLK/LT BLU) wire. For this test, go to: TEST 3: Making Sure The MAP Sensor Is Getting Ground.

CASE 2: The VIO/WHT wire DOES NOT have power (4.5 to 5 Volts). Check that the key is in the on position and that you're testing the correct wire and re-test.

If your multimeter still shows that the VIO/WHT wire DOES NOT have power, then you've found the reason why the MAP sensor did not create a voltage signal in TEST 1.

Although it's beyond the scope of this tutorial to find the reason why these 5 Volts are missing, you'll need to get yourself a wiring diagram (for your particular mini-van) and check the continuity of this wire between the MAP sensor and the PCM.

TEST 3: Making Sure The MAP Sensor Is Getting Ground

So far your tests have confirmed that:

• The MAP sensor's signal voltage does not decrease/increase as you apply/release vacuum to the sensor (TEST 1).
• The MAP sensor is receiving 5 Volts from the VIO/WHT wire (TEST 2).

For our last test we're gonna' make sure that the black with light blue stripe (BLK/LT BLU) wire is providing Ground to the MAP sensor.

In the photo above, the black with light blue stripe (BLK/LT BLU) wire is labeled with the number 3.

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

   Connect the black multimeter test lead to the BLK/LT BLU wire of the MAP sensor harness connector
   
   This is the wire that connects to the terminal labeled with the number 3.

4. 4

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

5. 5

   Have a helper turn the key to the On position, but don't crank or start the engine after the multimeter test leads have been set up.

6. 6

   Your multimeter should register 10 to 12 Volts DC if the BLK/LT BLU wire is feeding the MAP sensor with Ground.

Let's interpret your test results:

CASE 1: The multimeter registered 10 to 12 Volts DC. This confirms that the MAP sensor is getting Ground from the PCM. Now, since you have:

1. Confirmed that the MAP sensor is not creating an increasing/decreasing voltage signal (TEST 1).
2. Confirmed that the VIO/WHT wire is providing power (TEST 2).

And in this test step you have confirmed that the MAP sensor is getting Ground on the BLK/LT BLU wire then you can conclude that the MAP sensor is defective and needs to be replaced.

If you'd like to save a few bucks on the purchase of the MAP sensor, check out the section: Where To Buy The MAP Sensor And Save.

CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Re-check all of your test connections and repeat the test.

If the multimeter still does not show the indicated voltage, then you've found the reason why the MAP sensor did not create a voltage signal in TEST 1.

Although it's beyond the scope of this tutorial to find the reason why this Ground is missing, you'll need to get yourself a wiring diagram (for your particular mini-van) and check the continuity of this wire between the MAP sensor and the PCM.

More 2.5L Dodge Caravan And Plymouth Voyager Tutorials

You can find all of the 2.5L Dodge Caravan and 2.5L Plymouth Voyager tutorials in this index:

• Chrysler 2.5L Index Of Articles.

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

• How To Test A Blown Head Gasket (1991-1995 2.5L Caravan And Voyager).
• How To Test Engine Compression (1991-1995 2.5L Caravan And Voyager).
• Ignition System Wiring Diagram (1994-1995 2.5L Caravan And Voyager).
• How To Test The TPS (1991-1995 2.5L Caravan And Voyager).