How To Test The CKP Sensor (1996-1997 3.0L Caravan, Grand Caravan, Voyager, Grand Voyager)

The crankshaft position (CKP) sensor on the 1996-1997 3.0L V6 Caravan, Grand Caravan, Voyager, and Grand Voyager can easily be tested.

In this tutorial, I'll show you how to check CKP signal with a multimeter and how to check the sensor is getting power and Ground.

By the end of these three CKP sensor tests, you'll easily be able to determine if the CKP sensor is good or bad.

APPLIES TO: This tutorial applies to the following vehicles:

• 3.0L Dodge Caravan: 1996, 1997.
• 3.0L Dodge Grand Caravan: 1996, 1997, 1988, 1999, 2000.
• 3.0L Plymouth Voyager: 1996, 1997.
• 3.0L Plymouth Grand Voyager: 1996, 1997.

You can find the CKP sensor test for the 1998-2000 3.0L Caravan, Grand Caravan, Voyager, and Grand Voyager here:

• How To Test The Crankshaft Position Sensor (1998-2000 3.0L Caravan, Grand Caravan, Voyager, Grand Voyager)

Symptoms Of A Bad CKP Sensor

When the crankshaft position sensor fails, you'll usually notice one or more of the following issues:

• Engine No-Start Problem: Your car won't start if the CKP sensor is bad. This is by far the most common symptom of a bad CKP sensor.
• Stalling: The engine suddenly stalling is a common symptom of a failing CKP sensor, where it works most of the time, and the all of a sudden it doesn't.
• Check Engine Light: A failed or failing CKP sensor usually triggers the Check Engine light. If the fuel injection computer does set a CKP sensor diagnostic trouble code, you'll see this one:
  • P0320: No Crank Reference Signal At PCM

Here are some more specific symptoms of a bad crankshaft position sensor:

1. Auto Shutdown ASD Relay Disabled: The ASD relay does not activate and thus does not provide power to:
   • The fuel injectors.
   • The ignition coil.
   • The fuel pump relay and thus the fuel pump.
2. Ignition System Disabled: No spark firing from all of the spark plugs.
3. Fuel System Disabled: The fuel pump and fuel injectors are not activated when cranking the engine.

When troubleshooting a CKP sensor failure, the two most important signs to look for are:

• No spark from the spark plug wires as tested with a spark tester.
• No fuel injector pulses when using a Noid light when performing a fuel injector pulse test.

Generally, if you have spark in at least one spark plug wire, or if the Noid light indicates that you have injector pulses, then the CKP sensor is functioning properly. In this case, there's no need to test the CKP sensor further, as it's probably not the source of the engine no-start issue.

How The CKP Sensor Works

The crankshaft position sensor on the 1996-1997 3.0L Caravan (Grand Caravan, Voyager, Grand Voyager), is a Hall-Effect three wire crankshaft position sensor. As you turn the key and crank the engine, this is what happens:

1. Power Up and Grounding: The CKP sensor receives both power and Ground from the PCM.
   • Power is delivered to the sensor by the CKP sensor connector's orange (ORG) wire.
   • Ground is delivered to the sensor by the CKP sensor connector's black with light blue stripe (BLK/LT BLU) wire.
2. Magnetic Field: Inside the sensor, there's a magnet and a Hall-effect transducer (basically a small chip). The magnet creates a constant magnetic field around the sensor area.
3. Crankshaft Rotation: As the engine's crankshaft rotates, the notches on the flywheel's reluctor ring pass under the CKP sensor.
4. Disruption of Magnetic Field: Each time a notch passes under the sensor, it disrupts the magnetic field created by the magnet.
5. Voltage Change: This disruption is detected by the Hall-effect transducer. The chip then changes its output voltage, switching from a "low" state (0 Volts) to a "high" state (usually 5 Volts).
   • I'll be referring to this output voltage signal simply as the ON/OFF voltage signal in the tests.
6. Signal Wire: This change in voltage is sent as a pulse through the signal wire to the fuel injection computer.
7. Data Interpretation: The computer counts the number of pulses in a given time frame to determine the speed at which the crankshaft is rotating. This helps the computer to:
   • Adjust the ignition timing and start fuel injection.
   • Activate the Auto Shut Down (ASD) relay. In turn, the ASD relay activates:
     • The fuel pump relay and thus the fuel pump.
     • The fuel injectors.
     • The ignition coil and thus spark to each engine cylinder.

Since the crankshaft position sensor is a Hall Effect type sensor, its ON/OFF DC voltage signal output can be easily measured with:

• A multimeter.
• An oscilloscope.
• Or an LED Light.

This also means that there is no crankshaft position sensor resistance test to see if the crankshaft position sensor is bad or not. Only the 2-wire reluctor type crankshaft position sensor can be resistance tested.

CKP Sensor Connector Circuit Descriptions

NOTE: The illustration of the CKP sensor connector in this tutorial is of the engine wiring harness connector. This connector has round female terminals.

CKP Sensor Circuits
Terminal	Wire	Description
1	Orange (ORG)	8 Volts DC
2	Black with light blue stripe (BLK/LT BLU)	Ground
3	Grey with black stripe (GRY/BLK)	CKP Signal

What Tools Do I Need To Test The CKP Sensor?

The cool thing about testing the CKP sensor is that it doesn't require any expensive diagnostic tools. The following list of basic tools is what you'll need for the CKP sensor test described in this tutorial:

• A multimeter.
  • You can use a digital multimeter or an analog multimeter although the digital one is the preferred one.
  • If you don't have a multimeter or need to upgrade yours, check out my recommendation here: Buying A Digital Multimeter For Automotive Diagnostic Testing (at: easyautodiagnostics.com).
• 1/2 inch ratchet wrench.
  • You'll need to a 1/2 inch ratchet wrench and the appropriate socket to manually turn the crankshaft pulley by hand.
• A jack
• Jack stands
• 1/2 inch ratchet wrench and the necessary sockets to turn the crankshaft pulley.

Nothing that'll break the bank, right? And more than likely you already own most of them.

Where To Buy The CKP Sensor And Save

You can find the CKP sensor just about anywhere online or in an auto parts store. The following are my recommendations:

NOTE: It's important to avoid imitation parts and stick to known automotive brands such as: Airtex, Standard Motor Products, Delphi, and Evan-Fischer.

• Standard Motor Products PC34K Crankshaft Sensor (at: amazon.com)
• Airtex 5S1701 Crankshaft Position Sensor (at: amazon.com)

TEST 1: Testing The CKP Signal With A Multimeter

As mentioned earlier, when the engine is cranking (or running) the CKP sensor produces an ON/OFF voltage signal. This signal is sent to the fuel injection computer.

What we're going to do, is tap into the CKP signal wire with our multimeter and check that the CKP signal is generated as we manually turn the engine over.

I want to emphasize that the engine needs to be turned by hand, we're not going to be using the starter motor.

The wire that we're going to tap into is the gray with black (GRY/BLK) stripe wire of the CKP sensor's 3-wire connector. This is the wire that carries the CKP sensor signal to the fuel injection computer.

NOTE: The crankshaft position sensor must remain connected to its electrical connector to read the CKP signal. To access the CKP signal, inside the wire, you'll need to use a back probe on the connector or a wire piercing probe on the wire. You can see an example of this tool here: Wire Piercing Probe.

IMPORTANT: DO NOT remove the CKP sensor from the transmission's bell housing. If you do, the sensor's air gap calibration will get lost (when you reinstall the sensor) and it will get destroyed by the flywheel's reluctor ring. To learn more, see this section: CKP Sensor Air Gap Calibration (Paper Spacer)

Alright, this are the test steps:

1. 1

   Disconnect the ignition coil from its electrical connector. This is important! Do not proceed with the test without first unplugging the ignition coil.

2. 2

   Locate the CKP sensor's connector.
   
   Remove some of the plastic wire loom protector and/or the black electrical tape that shields the three wires of the CKP sensor. Remove enough of this electrical tape insulation to gain access to the three wires it protects.
   
   NOTE: This test is done on the engine wiring harness connector (not the connector that belongs to the CKP sensor itself). This connector has round female terminals.

3. 3

   Reconnect the crankshaft position sensor to its electrical connector if it was necessary to unplug it to remove some of the black electrical tape insulation on the wires.
   
   NOTE: The crankshaft position sensor must be connected to its electrical connector for this test to work.

4. 4

   Connect the black multimeter test lead directly on the battery negative (-) terminal.

5. 5

   Place the multimeter in Volts DC mode.

6. 6

   Connect the red multimeter test lead to the grey with black stripe (GRY/BLK) wire of the CKP sensor's engine wiring harness connector.
   
   The GRY/BLK wire connects to the female terminal labeled with the number 3 (in the illustration above) and its the CKP signal wire that transmits the crankshaft position (CKP) sensor signal to the PCM.

7. 7

   Turn the key to the RUN position (but don't crank the engine) when everything is set up. This will power up the CKP sensor.

8. 8

   Slowly turn the crankshaft pulley by hand in a clock-wise direction while you keep your eyes on the multimeter.
   
   You can manually turn the crankshaft pulley by using a 1/2" ratchet and socket on the crankshaft pulley bolt.
   
   IMPORTANT: Do not use the starter motor to crank the engine, since this will defeat the accuracy of this test.

9. 9

   The multimeter should register an ON/OFF voltage of 5 Volts DC as you manually turn the engine by hand.
   
   ON is when the multimeter displays 5 Volts DC and OFF is 0.5 Volts DC.
   
   The key to seeing this voltage change is to turn the crankshaft pulley slowly and steadily.

Alright, let's find out what your test result means:

CASE 1: The multimeter registered the ON/OFF 5 Volts DC as you manually turned the crankshaft pulley. This result confirms that the CKP sensor is creating a CKP signal and is functioning correctly.

You can also conclude that the crankshaft position sensor is not the cause of the engine's no-start problem.

CASE 2: The multimeter DID NOT register the ON/OFF 5 Volts DC as you manually turned the crankshaft pulley. This generally tells you that the CKP is bad.

But before we condemn the CKP sensor as bad, you need to verify that it's getting 8 Volts and Ground. Go to: TEST 2: Making Sure The CKP Sensor Is Getting 8 Volts.