How To Test The CKP Sensor (1995-2000 2.0L Dodge Stratus, Plymouth Breeze)

The 3-wire crankshaft position (CKP) sensor on the 1995-2000 2.0L Dodge Stratus (Plymouth Breeze) can't be tested by a simple resistance test, so in this tutorial, I'm gonna show you how to test it dynamically (and on the car).

All you need to test the CKP sensor is a simple multimeter set to Volts DC mode (no expensive scan tool needed). I'll walk you through the whole thing step by step.

You can find this tutorial in Spanish here: Cómo Probar El Sensor CKP (1995-2000 2.0L Dodge Stratus, Plymouth Breeze) (at: autotecnico-online.com).

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 pack.
   • 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 your 2.0L Dodge Stratus, 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 with white stripe (ORG/WHT) 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, its metal teeth (notches) pass by the CKP sensor as they rotate.
4. Disruption of Magnetic Field: Each time a tooth (or notch) passes by 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 pack 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

CKP Sensor Circuits
Terminal	Wire	Description
1	Orange with white stripe (ORG/WHT) 1995-1997 Only	8 Volts DC
	Orange (ORG) 1998-2000 Only	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?

You don't need any expensive tools to test the crankshaft position sensor. As a matter of fact, you don't even need a scan tool to test it. Here's what you'll need:

• 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).
• 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 buy the CKP sensor online, often cheaper than in-store prices. Check out the following links to help you comparison shop.

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

The very first thing we're gonna do is check that the CKP sensor is actually generating and sending out CKP signal pulses with a multimeter.

If you don't see any voltage pulses, you can pretty much say you've got a bad CKP sensor and it needs to be replaced (although we'll make sure by checking it's getting both power and Ground in TEST 2 and TEST 3).

As you're probably already aware, the crankshaft position sensor is located on the side of the engine that faces the firewall, right above the oil filter. It's inserted into the side of the engine block and is held in place by a small bolt.

We don't need to remove it to test it, we're gonna test it right where it is, but we do need access to its electrical connector. Which means that you'll need to lift the car to access it.

Safety first, though. Use jack stands to keep the car lifted —never trust the jack alone. I also suggest you use safety glasses to keep your eyes safe from any falling dirt/debris while working underneath the vehicle.

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.

Alright, this are the test steps:

1. 1

   Lift the front of the vehicle and place it on jack stands.
   
   CAUTION: Set the parking brake and/or place wheel chocks behind the rear wheels to keep the vehicle from rolling back.

2. 2

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

3. 3

   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 comfortable access to the three wires it protects.

4. 4

   Reconnect the crankshaft position sensor to its electrical connector now if it was necessary to unplug the connector from the crank (CKP) sensor to remove some of the black electrical tape insulation.
   
   NOTE: The crankshaft position sensor must be connected to its electrical connector for this test to work.

5. 5

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

6. 6

   Place the multimeter in Volts DC mode.

7. 7

   Connect the red multimeter test lead to the grey with black stripe (GRY/BLK) wire of the CKP sensor 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.

8. 8

   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.

9. 9

   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.

10. 10

    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 good CKP signal and is functioning correctly.

You can also conclude that the crankshaft position sensor is not the cause of your vehicle's no-start condition.

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.