How To Test The Camshaft Position Sensor (1998-2003 5.2L, 5.9L V8 Dodge Ram Pickup)

TEST 2: Making Sure The CMP Sensor Has 5 Volts

If you've made it this far, it means the CMP sensor didn't show any voltage switching between 5 Volts and 0 Volts back in TEST 1.

Chances are, the sensor isn't creating its ON/OFF signal because it's not getting power from the fuel injection computer.

So now, we're gonna check if the violet with white stripe (VIO/WHT) wire is supplying 5 Volts DC to the CMP sensor.

If that wire's got power, then we'll move on and make sure the sensor's getting a good Ground connection too.

Let's get to it:

1. 1

   Unplug the CMP sensor from its electrical connector.

2. 2

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

3. 3

   Switch your multimeter to DC Volts mode.

4. 4

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

5. 5

   With the red multimeter lead, probe the female terminal of the connector that connects to the VIO/WHT wire.
   
   The VIO/WHT wire is the one I've labeled with the number 3 in the photo above.
   
   NOTE: Make sure you're testing the engine wiring harness connector. This is the one with the female terminals.

6. 6

   Your multimeter should read somewhere between 4.5 and 5 Volts.

Now let's break down what your reading means:

CASE 1: You're getting 4.5 to 5 Volts on the VIO/WHT wire. That's exactly what you want to see.

The next step is to check for a solid Ground on the black with light blue stripe wire: TEST 3: Making Sure The CMP Sensor Has Ground.

CASE 2: You're NOT getting 4.5 to 5 Volts on the VIO/WHT wire. Without that power, the CMP sensor won't send out a signal.

What usually causes this is an open-circuit in the VIO/WHT wire somewhere between the CMP sensor and the computer.

Digging into the reason behind the missing 5 Volts is outside the scope of this tutorial, but your next move is to find the break and fix it.

TEST 3: Making Sure The CMP Sensor Has Ground

The camshaft position sensor also needs a solid Ground connection to generate its ON/OFF voltage signal.

In this final test, we're gonna check the black with light blue stripe (BLK/LT BLU) wire to make sure it's supplying Ground to the CMP sensor.

IMPORTANT: The CMP sensor gets its Ground from the fuel injection computer. Don't accidentally touch the BLK/LT BLU wire to 12 Volts —doing that will fry the computer. The method I'm showing you here is safe and accurate for checking Ground with a multimeter.

OK, these are the test steps:

1. 1

   Unplug the CMP sensor from its connector.

2. 2

   Attach the red lead from 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 —but don't crank the engine.

5. 5

   Touch the black lead to the female terminal of the connector that corresponds to the BLK/LT BLU wire.
   
   I've marked the BLK/LT BLU wire with the number 2 in the photo above.
   
   NOTE: Make sure you're testing the engine wiring harness connector. This is the one with the female terminals.

6. 6

   Your multimeter will show 10 to 12 Volts DC.

Here's how to read your results:

CASE 1: You see 10-12 Volts on the meter. That means the sensor is getting the Ground it needs. Perfect.

The camshaft position sensor is faulty and should be replaced if all of the following are true:

• The voltage signal didn't switch between 0 and 5 Volts during TEST 1.
• The VIO/WHT wire had 5 Volts during TEST 2.
• The BLK/LT BLU wire is delivering Ground (this test).

CASE 2: The multimeter didn't show any voltage. That means there's no Ground, and the CMP sensor can't produce its ON/OFF signal.

This is usually caused by a break in the BLK/LT BLU wire somewhere between the sensor's connector and the computer.

Tracking down the missing Ground is outside the scope of this tutorial —but your next step is to locate the problem and fix it.

More 5.2L, 5.9L V8 Dodge Ram Pickup Diagnostic Tutorials

I've written quite a few 'how to' diagnostic tutorials for the V8 Dodge Ram pickup and you can find them in this index:

• 5.2L, 5.9L V8 Dodge Ram Pickup 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 (1998-2003 5.2L, 5.9L V8 Dodge Ram Pickup).
• How To Test The Fuel Pump (1992-2003 5.2L, 5.9L V8 Dodge Ram Pickup).
• How To Test The TPS (1997-2003 5.2L, 5.9L V8 Dodge Ram Pickup).
• Testing The Oxygen Sensors (1996-2003 5.2L, 5.9L V8 Dodge Ram Pickup).