How To Test The Crankshaft Position Sensor (1994-1996 3.9L Dodge Dakota)

TEST 2: Making Sure The CKP Sensor Has Power

If in TEST 1 the crankshaft position (CKP) sensor on your Dodge Dakota did not produce an ON/OFF voltage signal then there's a good chance that it might not be receiving power.

If your 3.9L Dodge Dakota is a 1994-1995 model, then this power is in the form of 8 Volts DC and the wire that feeds these 8 Volts to the CKP sensor is the orange (ORG) wire of the engine wiring harness connector.

If your 3.9L Dodge Dakota is a 1996 model, then this power is in the form of 5 Volts DC and the wire that feeds these 5 Volts to the CKP sensor is the violet with white stripe (VIO/WHT) wire of the engine wiring harness connector.

In the photo above, the female terminal that provides these 5 or 8 Volts DC to the CKP sensor is labeled with the number 1.

If the CKP sensor is getting power (8 Volts or 5 Volts), then our next step is to make sure that it's getting Ground in TEST 3.

NOTE: Avoid probing the front of the female terminal with your multimeter test lead or you run the risk of damaging the terminal. Use a back-probe on the back of the connector or use a wire-piercing probe on the wire.

These are the test steps:

1. 1

   Disconnect the CKP sensor from its connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

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

4. 4

   Connect the red multimeter test lead (using the appropriate tool) to the wire that connects to terminal #1.
   
   On the 1994-1995 3.9L Dodge Dakota this is an ORG wire.
   
   On the 1996 3.9L Dodge Dakota this is a VIO/WHT wire.

5. 5

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

6. 6

   Your multimeter should read:
   
   7 to 8 Volts DC (1994-1995 3.9L Dodge Dakota).
   
   4 to 5 Volts DC (1996 3.9L Dodge Dakota).

Let's examine your test result:

CASE 1: The CKP sensor is getting power. This is the correct and expected test result.

The next and last test is to make sure that the BLK/LT BLU wire is feeding the CKP sensor with Ground. Go to: TEST 3: Making Sure The CKP Sensor Has Ground.

CASE 2: The CKP sensor is not getting power. Without this voltage the crankshaft position sensor will not produce a CKP voltage signal.

The most likely cause of these missing 8 or 5 Volts is an open-circuit problem in the ORG or VIO/WHT wire between the CKP sensor's connector and the fuel injection computer's connector.

Although it's beyond the scope of this tutorial to check for this missing power, your next step is to find out why it's missing and restore it.

TEST 3: Making Sure The CKP Sensor Has Ground

Your previous two tests have confirmed that:

• The crankshaft position sensor is not creating an ON/OFF signal (TEST 1).
• The crankshaft position sensor is getting 8 Volts DC (TEST 2).

For our last test we're going to make sure that the CKP sensor is getting Ground.

This Ground is provided to the crankshaft position sensor by the black with light blue stripe (BLK/LT BLU) wire.

The black with light blue stripe (BLK/LT BLU) wire connects to the female terminal labeled with the number 2 in the photo above.

To test for the presence of Ground in this wire, we're going to do a simple multimeter voltage test just like the one we did to check for the presence of 8 Volts DC in the orange (ORG) wire in TEST 2.

IMPORTANT: Be careful and don't short the BLK/LT BLU wire to battery power or you'll fry the fuel injection computer. The multimeter voltage test suggested below (for testing the presence of Ground) is a safe and accurate test.

NOTE: Avoid probing the front of the female terminal with your multimeter test lead or you run the risk of damaging the terminal. Use a back-probe on the back of the connector or use a wire-piercing probe on the wire.

These are the test steps:

1. 1

   Disconnect the CKP sensor from its connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

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

4. 4

   Connect the black multimeter test lead (using the appropriate tool) to the wire that connects to terminal #2.
   
   This wire is the BLK/LT BLU of the connector.

5. 5

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

6. 6

   Your multimeter should read 10 to 12 Volts DC if the BLK/LT BLU wire is providing Ground.

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

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

You can now conclude that the crankshaft position (CKP) sensor is defective if you have:

• Confirmed that the crankshaft position sensor is not creating an ON/OFF signal (TEST 1).
• Confirmed that the crankshaft position sensor is getting power (TEST 2).
• Confirmed that the crankshaft position sensor is getting Ground (this test section).

CASE 2: Ground is NOT present in the BLK/LT BLU wire. Without Ground the crankshaft position sensor will not produce a CKP voltage signal.

The most likely cause of this missing Ground is an open-circuit problem in the BLK/LT BLU wire between the CKP sensor's connector and the fuel injection computer's connector.

Although it's beyond the scope of this tutorial to check for this missing Ground, your next step is to find out why it's missing and restore it.

More 3.9L Dodge Dakota Tutorials

You can find a complete list of 3.9L Chrysler and Dodge 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).