Testing the crankshaft position (CKP) sensor is not difficult and as a matter of fact, you don't need any expensive diagnostic test equipment to do it.
In this tutorial, I'm gonna' show you how to test it using a multimeter. No scan tool is required (tho' it's an awesome tool to have).
Contents of this tutorial:
- Symptoms Of A Bad Crankshaft Position (CKP) Sensor.
- Circuit Descriptions Of The Crankshaft Position Sensor.
- Where To Buy The Crankshaft Position Sensor.
- TEST 1: Testing The Crankshaft Position Signal.
- TEST 2: Making Sure The CKP Sensor Has Power.
- TEST 3: Making Sure The CKP Sensor Has Ground.
- More 3.9L Dodge Dakota Tutorials.
You can find this tutorial in Spanish here: Cómo Probar El Sensor De La Posición Del Cigüeñal (1994-1996 3.9L Dodge Dakota) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles since they use the exact same crankshaft position (CKP) sensor:
- 3.9L V6 Dodge Dakota: 1994, 1995, 1996.
IGNITION COIL TEST: The following tutorial will help you test the ignition coil: How To Test The Ignition System (1992-1997 3.9L Dodge Dakota).
WIRING DIAGRAM: You can find the ignition system wiring diagrams here:
- Ignition System Circuit Diagram (1992-1993 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1994-1995 3.9L Dodge Dakota).
- Ignition System Circuit Diagram (1996 3.9L Dodge Dakota).
Symptoms Of A Bad Crankshaft Position (CKP) Sensor
A crankshaft position (CKP) sensor will usually fail in one of two ways. It will either fail completely and your 3.9L Dodge Dakota will crank but not start due to a lack of spark.
Or the crankshaft position sensor will fail intermittently. In this type of failure, the sensor works fine most of the time but every now and then it does not. And when it stops working, the engine will not start or if it's running, the engine will stall (die).
Although the fuel injection computer is designed to set a trouble code when the crankshaft position sensor fails, it doesn't always do so. But when it does set a trouble code, you'll see:
- Code 11: No Crankshaft Reference Signal At PCM (1994-1995 OBD I system).
- P0320: No Crank Reference Signal At PCM (1996 OBD II system).
If your 3.9L Dodge Dakota is not starting or if it stalls intermittently while running and if you have a scan tool, check for trouble codes.
Circuit Descriptions Of The Crankshaft Position Sensor
The crankshaft position sensor is a 3-wire sensor and it's a Hall Effect sensor. Since it's a Hall Effect sensor, it needs power and Ground to generate its position signal.
Power is in the form of 8 Volts DC (1994-1995 3.9L Dakota) or 5 Volts DC (1996 3.9L Dodge Dakota). This voltage is provided by your 3.9L Dodge Dakota's fuel injection computer. Ground is also provided by the fuel injection computer.
The connector on the sensor itself has male spade terminals. The connector on the engine wiring harness has female terminals.
Since we'll be testing for the presence of the CKP signal, 8 Volts (or 5 Volts), and Ground, we'll need to know the job description of each of the 3 wires. With this in mind take a look at the following table:
| 1994-1995 Crankshaft Position Sensor Connector | ||
|---|---|---|
| Pin | Wire Color | Description |
| 1 | Orange (ORG) | Power (8 Volts DC) |
| 2 | Black with light blue stripe (BLK/LT BLU) | Sensor Ground |
| 3 | Gray with black stripe (GRY/BLK) | CKP Signal |
| 1996 Crankshaft Position Sensor Connector | ||
|---|---|---|
| Pin | Wire Color | Description |
| 1 | Violet with white stripe (VIO/WHT) | Power (5 Volts DC) |
| 2 | Black with light blue stripe (BLK/LT BLU) | Sensor Ground |
| 3 | Gray with black stripe (GRY/BLK) | CKP Signal |
Where To Buy The Crankshaft Position Sensor
Checkout the following links and comparison shop the crankshaft position sensor for your 1994, 1995, or 1996 V6 Dodge Dakota:
With Automatic Transmission:
With Standard Transmission:
TEST 1: Testing The Crankshaft Position Signal
As mentioned at the beginning of the tutorial, we're going to test the crankshaft position sensor with a multimeter.
What makes this multimeter test possible is the fact that the crankshaft position sensor produces an ON/OFF voltage signal.
To be a bit more specific on is when the CKP signal is at 5 Volts. And off is when the CKP signal is at 0 Volts.
This ON/OFF voltage is only produced when the engine is turning.
To test for this ON/OFF voltage signal, we're going to have to turn the engine and since we're using multimeter we need to turn the engine manually. In other words were not going to use the starter motor.
If the crankshaft position sensor is bad, then it's going to stay stuck producing a single voltage value as we turn the engine.
In other words, the crankshaft position sensor is not going to produce the ON/OFF voltage signal as we manually turn the engine.
Before we start let me tell you that your 3.9L Dodge Dakota comes equipped with a camshaft position sensor and a crankshaft position sensor. The camshaft position sensor is located in the distributor and the crankshaft position sensor is bolted onto the transmission bell housing. Both of the connectors are in the same location so take care to test the correct connector.
IMPORTANT: The crankshaft position sensor must be connected to its engine harness connector for this test to work. You'll need to connect your multimeter test lead to a back probe or a wire piercing probe to read the crank signal. You can see an example of a wire piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01).
NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Buying A Digital Multimeter For Automotive Diagnostic Testing.
These are the test steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the ignition coil from its electrical connector. This is an important safety precaution!
- 3
With the red multimeter test lead, probe the gray with black stripe (GRY/BLK) wire of the crank sensor connector.
NOTE: The crankshaft position sensor must remain connected to its engine wiring harness connector to be able to read its signal. - 4
Connect the black multimeter test lead directly on the battery negative (-) terminal.
- 5
Turn the ignition key to the ON position but don't crank or start the engine.
- 6
Turn the engine by hand using the 1/2" ratchet wrench and appropriate socket on the crankshaft pulley. For the accuracy of the test, do not use the starter motor.
- 7
Your multimeter will read an ON/OFF voltage of 5 Volts and 0 Volts as you turn the engine (if the crankshaft position sensor is functioning correctly).
ON is when the multimeter reads 4-5 Volts DC and OFF is when it reads 0 Volts DC.
Let's examine your CKP signal test result:
CASE 1: The multimeter read the indicated ON/OFF DC voltage. This is the correct and expected test result and tells you that the crankshaft position sensor is functioning correctly.
Since the crankshaft position sensor IS NOT defective, something else is causing your 3.9L V6 Dakota to not start.
CASE 2: The multimeter DID NOT read the indicated ON/OFF DC voltage. This test result usually means that the crankshaft position sensor is defective.
Before you replace it, make sure it's getting power and Ground. For the next test go to: TEST 2: Making Sure The CKP Sensor Has Power.