TEST 2: Making Sure The Crank Sensor Has Power
Usually when the crankshaft position (CKP) sensor does not produce an ON/OFF signal, it's because it's bad. But to be sure, we need to make sure it's getting power.
On the 1997-1999 3.9L Dodge Dakota, the crankshaft position sensor receives 5 Volts thru' the violet with white stripe (VIO/WHT) wire of the engine wiring harness connector.
On the 2000-2003 3.9L Dodge Dakota, the crankshaft position sensor receives 5 Volts thru' the orange (ORG) wire of the engine wiring harness connector.
We'll use our multimeter to make sure these 5 Volts are present in the VIO/WHT (or ORG) wire.
These are the test steps:
- 1
Disconnect the CKP sensor from its connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Turn the key on but don't crank or start the engine.
- 4
Connect the red multimeter test lead (using the appropriate tool) to the wire that connects to terminal #1.
On the 1998-1999 3.9L Dodge Dakota, this wire will be VIO/WHT.
On the 2000-2003 3.9L Dodge Dakota, this wire will be ORG. - 5
Connect the black multimeter test lead to the negative (-) battery terminal.
- 6
Your multimeter should read 4.5 to 5 Volts DC.
Let's examine your test result:
CASE 1: 4.5 to 5 Volts DC are present in the VIO/WHT (or ORG) wire. 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 Crank Sensor Has Ground.
CASE 2: 4.5 to 5 Volts DC are NOT present in the VIO/WHT (ORG) wire. Without this voltage the crankshaft position sensor will not produce a CKP voltage signal.
The most likely cause of these missing 5 Volts is an open-circuit problem in the VIO/WHT (or ORG) 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 Crank Sensor Has Ground
So far your test results have confirmed that:
- The crankshaft position sensor is not creating an ON/OFF signal (TEST 1).
- The crankshaft position sensor is getting power (TEST 2).
In this last test section, we're gonna' make sure that it's getting Ground.
Ground is fed to the sensor thru' the black with light blue stripe (BLK/LT BLU) wire of the engine wiring harness connector.
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.
These are the test steps:
- 1
Disconnect the CKP sensor from its connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Turn the key on but don't crank or start the engine.
- 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
Connect the red multimeter test lead to the positive (+) battery terminal.
- 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 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:
Here's a small sample of the tutorials you'll find in the index:
- Testing The Ignition System (1998-2003 3.9L Dodge Dakota).
- How To Test The MAP Sensor (2000-2003 3.9L V6 Dodge Dakota).
- How To Test The TPS Sensor (2000-2003 3.9L V6 Dodge Dakota).
- How To Test For A Blown Head Gasket (1993-1999 3.9L Dodge Dakota).
- Engine Management Sensor Circuit Diagram (1994-1995 3.9L V6 Dodge Dakota).
If this info saved the day, buy me a beer!
