How To Test The Crankshaft Position Sensor (1992-1997 3.9L V6 Dodge Ram Pickup)

TEST 2: Making Sure The CKP Sensor Has Power

Since the crankshaft position (CKP) sensor is a Hall-Effect type sensor, it needs both power and Ground to function properly.

In this step of the CKP sensor check, you're gonna use your multimeter to confirm that the sensor's getting the power it needs.

Here's what you're looking for: depending on the year of your V6 Dodge Ram, the PCM sends either 8 or 5 Volts DC to the sensor when the key's in the ON position (and also when the engine's turning over or running).

If you're working on a 1992–1995 model, the power comes through the orange (ORG) wire —that one delivers 8 Volts.

If it's a 1996–1997 pickup, then the purple with white stripe (PPL/WHT) wire is the one you want —it sends out 5 Volts from the PCM.

Here's what you're gonna do next:

1. 1

   Disconnect the CKP sensor from the engine wiring harness connector.

2. 2

   Hook the black lead from your multimeter to the battery's negative (-) post.

3. 3

   Turn the key to the ON position —no need to crank the engine for this step.

4. 4

   Set your multimeter to read Volts DC.

5. 5

   Touch the red multimeter lead to female terminal 1 on the CKP sensor harness connector.
   
   Make sure that terminal lines up with either the ORG or VIO/WHT wire.
   
   NOTE: This test happens at the engine harness connector —the side with the female terminals.

6. 6

   Your multimeter should show between 7.5 to 8 Volts -or- 4.5 and 5 Volts DC if the PCM is sending power like it's supposed to.

Now let's go over what those readings tell you:

CASE 1: You're getting the indicated voltage. That means the CKP sensor is getting its power from the PCM —so far, so good.

But don't call it yet —you've still got to confirm the sensor has a solid Ground. That's up next: TEST 3: Making Sure The CKP Sensor Has Ground.

CASE 2: You're not getting any voltage. First, double-check your test connections and try again.

If there's still no voltage, you've found the issue: the CKP sensor isn't getting power, and replacing it isn't the solution to the problem.

Tracking down what's causing that missing voltage is beyond what we're covering here —but fixing that power supply will get your V6 Dodge Ram pickup back on the road.

TEST 3: Making Sure The CKP Sensor Has Ground

So far, your CKP sensor tests have revealed the following:

• TEST 1: The sensor isn't sending out a 5-Volt ON/OFF signal.
• TEST 2: The power supply wire is delivering 8 or 5 Volts DC to the sensor like it should.

Now it's time for the last piece of the puzzle —we're gonna check if the sensor has a good Ground connection. You'll do this with a quick voltage test using your multimeter.

The sensor's Ground comes through the black with light blue stripe (BLK/LT BLU) wire, which runs straight to the PCM.

IMPORTANT: Handle this part with care. That BLK/LT BLU wire connects directly to the PCM —if it touches battery voltage, you'll fry the computer. The test method I'm about to show you is 100% safe for checking that wire's Ground.

Here's what you'll need to do:

1. 1

   Disconnect the CKP sensor from its wiring harness.

2. 2

   Hook up the red lead from your multimeter to the battery's positive (+) terminal.

3. 3

   Turn the ignition key to ON. No need to start the engine.

4. 4

   Set your multimeter to read DC Volts.

5. 5

   Gently probe terminal number 2 of the CKP sensor connector with the black multimeter test lead.
   
   Make sure this terminal connects to the BLK/LT BLU wire —that's the one carrying Ground from the PCM.

6. 6

   If everything's working right, you'll see somewhere between 10 and 12 Volts DC on your multimeter.

Now let's go over what it all means:

CASE 1: You saw 10 to 12 Volts DC. That means the BLK/LT BLU wire is doing its job and supplying Ground to the CKP sensor.

If all three of your tests check out:

• TEST 1: No ON/OFF signal from the sensor.
• TEST 2: Power wire is delivering 5 or 8 Volts.
• This test: Ground is present and solid.

Then the sensor itself is shot —time to replace it.

CASE 2: You didn't get a 10–12 Volt reading. Go back and double-check your test setup, then try again.

If there's still no voltage showing, the BLK/LT BLU wire isn't supplying Ground. That means the CKP sensor isn't the problem —the missing Ground is. Your next step is to resolve the issue causing this missing Ground.

More 3.9L V6 Dodge Ram Pickup Tutorials

You can find a complete list of wiring diagrams and diagnostic tutorials for the V6 Dodge Ram pickup here:

• 3.9L V6 Dodge Ram Index Of Articles.

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

• How To Test The Fuel Pump (1992-2001 3.9L V6 Dodge Ram Pickup).
• How To Test The Intake Air Temp (IAT) Sensor (1992-1997 3.9L V6 Dodge Ram Pickup).
• How To Test The TPS (1992-1996 3.9L V6 Dodge Ram Pickup).
• How To Test For A Blown Head Gasket (1989-2001 3.9L V6 Dodge Ram Pickup).