How To Test The Camshaft Position Sensor (1996-1997 5.2L, 5.9L V8 Dodge Ram Van)

TEST 2: Making Sure The CMP Sensor Has 5 Volts

If you've made it here, your TEST 1 result confirms the CMP sensor isn't switching between 5 Volts and 0 Volts.

In some cases, the CMP doesn't generate its ON/OFF signal because the violet with white stripe (VIO/WHT) wire isn't delivering power from the fuel injection computer.

Now, we're gonna check the VIO/WHT wire and see if it's supplying 5 Volts DC to the CMP sensor.

If the VIO/WHT wire checks out and you see 5 Volts, the next step is to confirm the sensor's also getting a good Ground.

Here's what you need to do:

1. 1

   Disconnect the CMP sensor from its connector.

2. 2

   Hook up the black lead of your multimeter to the battery's negative (-) terminal.

3. 3

   Set the meter to read DC Volts.

4. 4

   Turn the key to the ON position —but don't start or crank the engine.

5. 5

   Use the red lead to touch the front of female terminal 1. Refer to the illustration of the connector above to ID the terminal on your van's CMP sensor connector.
   
   It's important that you confirm that the terminal actually corresponds to the VIO/WHT wire.
   
   NOTE: This voltage check happens at the engine wiring harness connector —the one with the female terminals.

6. 6

   The multimeter should read between 4.5 and 5 Volts.

Time to look at what your test result means:

CASE 1: The VIO/WHT wire is supplying 4.5 to 5 Volts. Perfect —that's exactly what you're looking for.

Your next step is to check for Ground, which is supplied by the black with light blue stripe wire. Go to: TEST 3: Making Sure The CMP Sensor Has Ground.

CASE 2: The VIO/WHT wire is NOT supplying 4.5 to 5 Volts. Without that voltage, the CMP sensor can't send out its signal —simple as that.

The most common cause of this missing voltage is an open-circuit problem in the VIO/WHT wire between the sensor connector and the fuel injection computer.

Your job now is to track down and fix the break in that power feed. That part's not covered in this tutorial, but you'll need to find where the voltage is dropping and get it back.

TEST 3: Making Sure The CMP Sensor Has Ground

Alright, by now you've confirmed two things:

• The CMP signal isn't flipping between 0 and 5 Volts (TEST 1).
• The VIO/WHT wire is feeding it 4.5 to 5 Volts just fine (TEST 2).

So now it's time to check the black with light blue stripe (BLK/LT BLU) wire and make sure it's giving the sensor a solid Ground.

IMPORTANT: That Ground comes straight from the fuel injection computer. Never short the BLK/LT BLU wire to 12 Volts —you'll fry the PCM. The multimeter test I'm outlining below is a safe way to check for Ground.

Let's begin:

1. 1

   Unplug the CMP sensor from its connector.

2. 2

   Connect the red lead of your multimeter to the battery's positive (+) terminal.

3. 3

   Set your multimeter to DC Volts mode.

4. 4

   Turn the ignition key to the ON position —don't start or crank the engine.

5. 5

   Use the black lead to touch the front of female terminal 2. Refer to the illustration of the connector above to ID the terminal on your van's CMP sensor connector.
   
   It's important that you confirm that the terminal actually corresponds to the BLK/LT BLU wire.
   
   NOTE: This voltage check happens at the engine wiring harness connector —the one with the female terminals.

6. 6

   If the Ground is good, the meter should read somewhere between 10 and 12 Volts.

Here's what your results tell you:

CASE 1: Ground is present at the BLK/LT BLU wire. That means the CMP sensor's getting the Ground it needs.

If there's still no signal coming from the sensor, it's time to replace it —but only if all of the following are true:

• The CMP signal didn't flip between 0 and 5 Volts during TEST 1.
• 5 Volts showed up on the VIO/WHT wire in TEST 2.
• You confirmed Ground on the BLK/LT BLU wire in this test.

CASE 2: No Ground at the BLK/LT BLU wire. Without Ground, the CMP sensor can't send out a signal —it's dead in the water.

This usually means there's a break in the BLK/LT BLU wire somewhere between the sensor connector and the fuel injection computer.

Finding that bad Ground wire is your next move. It's not covered in this guide, but you'll need to trace the circuit and fix the issue.

More 3.9L V6 Dodge Ram Van Diagnostic Tutorials

I've written quite a few tutorials that may help you troubleshoot the issues on your V6 Dodge Ram van. You can find them in this index:

• 3.9L V6 Dodge Ram Van Index Of Articles.

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

• How To Test The Intake Air Temp (IAT) Sensor (1992-1997 3.9L V6 Dodge Ram Van).
• How To Test The TPS (1992-1997 3.9L V6 Dodge Ram Van).
• How To Test For A Blown Head Gasket (1989-2003 3.9L V6 Dodge Ram Van).
• How To Test The Engine Compression (1989-2003 3.9L V6 Dodge Ram Van).