TEST 2: Making Sure The CMP Sensor Has Power
If your test result for TEST 1 indicated that the camshaft position sensor is not producing an ON/OFF voltage signal as you cranked the engine, then the next test is to confirm that it's getting 5 Volts DC.
On the 1998-1999 3.9L Dodge Dakota and 3.9L Dodge Durango, these 5 Volts are supplied by the violet with white (VIO/WHT) wire of the connector.
On the 2000-2003 3.9L Dodge Dakota, these 5 Volts DC are supplied by the orange (ORG) wire of the connector.
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
Disconnect the CMP 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 power wire identified with the number 1 in the photo above.
On the 1998-1999 3.9L Dodge Dakota this is an VIO/WHT wire.
On the 2000-2003 3.9L Dodge Dakota this is a ORG wire. - 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 analyze your test result:
CASE 1: The CMP sensor is getting 5 Volts DC. This is the correct and expected test result.
The next and last test is to make sure that Ground is present in the BLK/LT BLU wire of the connector. For this test go to: TEST 3: Making Sure The CMP Sensor Has Ground.
CASE 2: The CMP sensor is not getting 5 Volts DC. Without this voltage the camshaft position sensor will not produce a CMP voltage signal.
A lack of 5 Volts is usually due to an open-circuit problem in the ORG or VIO/WHT wire between the CMP 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 CMP Sensor Has Ground
Your test results (TEST 1 and TEST 2) have confirmed that:
- The camshaft position sensor is not creating an ON/OFF signal (TEST 1).
- The camshaft position sensor is getting 5 Volts DC (TEST 2).
Now we're gonna' check for the presence of Ground in the black with light blue stripe (BLK/LT BLU) wire of the CMP sensor's 3-wire connector.
In the photo above, the black with light blue stripe (BLK/LT BLU) wire is labeled with the number 2.
IMPORTANT: Be careful and don't short the BLK/LT BLU wire to battery power (12 Volts) or you'll fry the fuel injection computer. The multimeter voltage test I'm suggesting below (for testing the Ground circuit) 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
Disconnect the CMP 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 Ground wire identified with the number 2 in the photo above.
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: The BLK/LT BLU wire has Ground. This is the correct test result and lets you know that the camshaft position sensor is getting Ground.
The camshaft position sensor is bad and needs to be replaced if you have:
- Confirmed that the camshaft position sensor IS NOT creating an ON/OFF voltage signal (TEST 1).
- Confirmed that 5 Volts are being fed to the camshaft position sensor (TEST 2).
- Confirmed that Ground is being fed to the camshaft position sensor (this test section).
CASE 2: The BLK/LT BLU wire DOES NOT have Ground. The camshaft position sensor will not produce a CMP voltage signal if it doesn't get Ground in the BLK/LT BLU wire.
The most likely cause of this missing Ground is an open-circuit problem in the BLK/LT BLU wire between the CMP 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:
- 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).
If this info saved the day, buy me a beer!
