How To Test 3 Wire Crank Sensor With Multimeter

If your car won’t start, it may be the 3 wire crank sensor. The crank sensor tells the engine control unit (ECU) when to fire the spark plugs. To test the sensor, you need a multimeter that can test three wires. 

Three-wire sensors have two terminals, one on each end. In this article, you will learn step-by-step instructions on how to test your sensor and diagnose the problem with it.

Signs Your Camshaft Position Sensor Is Failing

Dorman 907-819 Magnetic Camshaft Position Sensor for Select Acura/Honda Models

Your vehicle’s  camshaft position sensor is monitored by the engine control module (ECM). The ECM determines if the engine is running. If the ECM is not receiving a signal, it will set a trouble code. 

Symptoms of a bad sensor include:

Car Jerking and Losing Power

If the crank sensor malfunctions, the engine may experience jerking or lurching during acceleration. 

Transmission Locking in a Single Gear Until You Turn It Off and Restart

Use extreme caution if this happens. You’ll normally notice the check engine light starts to come on just before or just after your vehicle gets stuck in gear. 

Loss of Engine Power; for Example, No Acceleration Above 35 Mph

This can be because the sensor is faulty or not reading the correct information, or because the sensor is not transmitting information to the car’s ECU (Engine Control Unit / Computer) at all.

The Check Engine Indicator Is On

A flashing check engine light indicates there’s a problem with your vehicle, and that it may not be safe to drive. 

Vehicle Won’t Start

If the 3-wire crank sensor is worn out, the ignition system can’t tell the ECU (Engine Control Unit / Computer) to start the car..

Poor Acceleration

Poor acceleration is a problem that can range from annoying to dangerous. If your acceleration is severely limited, you could be putting yourself and others at risk.

Increased Fuel Consumption

If your vehicle is experiencing an increased fuel consumption, the camshaft position sensor may be to blame. The camshaft position sensor is responsible for the fuel, timing, and ignition of the vehicle. 

Misfiring

If this is your first time encountering the Camshaft Position Sensor (aka the crank sensor), take it from us—you’re not alone. So, if your car is constantly misfiring, the crank sensor could certainly be the cause.

Hard Starting

If the ECM receives proper input from the crank position sensor, it can determine the position of the camshaft. If the ECM does not receive a signal from the sensor, the engine may start hard or not start whatsoever.

Surging

You might notice surging when the weather is colder if you have a bad crank sensor. This is because a car’s engine is usually one of the hottest components in the car.

No Spark: No Start at All

If your car suddenly stops while on  the road or in your driveway, the problem is rarely a battery or alternator issue. More often than not, the cause of the problem is a faulty camshaft position sensor.

No Fuel Injector Pulse

A failing camshaft position sensor can result in a No Fuel Injector Pulse. It sometimes can be misdiagnosed by the novice mechanic.

How To Test 3 Wire Crank Sensor With Multimeter

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Testing the CKP Signal With a Multimeter

Raise the Front of the Pickup or SUV and Then Lower It on Jack Stands

  • Always be sure you find a level place before you place your vehicle on jacks..

Disable the Fuel System

  • Most modern vehicles have a fuse to disable the fuel system. Simply pull it out. You can also unplug the wiring harness to the fuel pump.

Disable the Ignition System

  • This is probably another fuse you’ll pull out. Consult your vehicle’s owners manual if you cannot locate the fuse. 

Connect the Red Multimeter Test Lead to the Wire Labeled With the Letter “C”

  • This step will check to see if the wiring from the sensor is properly grounded. 

Connect the Black Multimeter Test Lead to the Battery Negative (-) Terminal

  • Connecting a black multimeter tester to the battery negative (-) terminal will enable you to test the crankshaft position sensor with the multimeter. 

Turn the Key to the On (RUN) Position

  • Just supply the vehicle with power, but do NOT crank the engine.

Place Your Multimeter in Volts DC Mode

  • Be absolutely certain you have the device set to the proper current.

Manually Turn the Engine by Hand

  • This can be done by turning the engine by hand with a ratchet on a cold start and checking the voltage on the pink wire of the ignition harness.

The Multimeter Will Register an ON/OFF Voltage Signal

  • This is the most accurate way. You can connect the multimeter to the 3-wire crank sensor and the multimeter will register an ON/OFF voltage signal. 

Interpretation of Multimeter Results

Case #1 (Working) the Multimeter Registered the ON/OFF Voltage As You Turned the Engine With the Ratchet:

  • The multimeter registered the ON/OFF voltage as you turned the engine with the ratchet. This means that the Crank Sensor is operating normally. The Crank Sensor should be reading 10-12 volts DC with the multimeter.

Case #2 (Not Working) the Multimeter DID NOT Register the ON/OFF Voltage Signal As You Turned the Engine With the Ratchet:

  • This usually means that the Crank Sensor is at fault, and may need to be replaced. 

Move to the next step below. 

Test 2: Making Sure CKP Is Getting Power

The Crankshaft Position (CKP) sensor is a device used in modern vehicles to indicate to the engine control module (ECM) that the engine has reached Top Dead Center (TDC). 

This sensor is an inductive sensor that uses a rotating magnetic field to generate a rotating magnetic field. The rotating magnetic field is used to measure the position of the crankshaft. 

This test will determine if the CKP is actually getting power.

Place the Multimeter in Volts DC Mode

  • To determine whether the multimeter is in the correct mode, check the resistance setting at the same time. The resistance dial should be set to the highest resistance setting.

Disconnect the Crankshaft Position Sensor From Its Electrical Connector

  • When troubleshooting the 3 wire crank sensor, it is a good idea to remove the sensor from the car and test it. 

Connect the Red Multimeter Test Lead to the Wire Labeled With the Letter “A”

  • Disconnect the negative battery terminal and wait at least three minutes before beginning. 

Connect the Black Multimeter Test Lead to the Battery Negative (-) Post

  • Just be sure to mark the wire you have disconnected from the sensor so you don’t mix it up when reconnecting the wire to the sensor.

Turn the Key ON but Don’t Crank the Engine

  • You’ll only need to supply power to the circuitry, not start the engine.

Your Multimeter Should and Will Register 10 to 12 Volts

  • The sensor receives a signal from the ignition switch and sends it to the ignition control module or ECM.

Interpretation of Multimeter Results

Case #1 (Working) 10 to 12 Volts Registered on the Multimeter When the Ignition Was Turned ON:

  • This means that the crank sensor is working fine with no problems. 

Case #2 (Not Working) 10 to 12 Volts DID NOT Register When the Ignition Was Turned ON:

  • This tells you that the problem is going to be a faulty crank sensor. It’s probably time to replace it,but let’s complete our check of the CKP sensor first.

Move to the next step below. 

Test 3: Making Sure The CKP Sensor Is Getting Ground

Place the Multimeter in Volts DC Mode

  • DC mode is used to check for a ground

Disconnect the Crankshaft Position Sensor From Its Electrical Connector

  • This step isolates the sensor for easier troubleshooting. 

Connect the Black Multimeter Test Lead to the Wire Labeled With the Letter “B”

  • Always check that you are probing the correct terminal.

Connect the Red Multimeter Test Lead to the Battery Positive (+) Terminal

  • This step will read voltage when the vehicle has power applied to it.

Turn the Key On but Don’t Crank the Engine

  • You’ll just need to apply power to the wiring or this step.

Your Multimeter Should Register 10 to 12 Volts DC

Interpretation of Multimeter Results

Case #1 (Working) the Multimeter Showed 10 to 12 Volts When the Ignition Was Turned ON:

  • This tells you that the fuel injection portion is receiving proper ground. But if test one is good and test 2 is bad, then the problem is the cranks sensor. 

Case #2 (Not Working) the Multimeter DID NOT Show 12 Volts When the Ignition Was Turned ON:

  • This let’s you know that the fuel injection portion of the computer is NOT receiving proper ground

Wrapping Up

We hope you enjoyed learning how to test a 3 wire crank sensor with a multimeter. As you could tell, it’s pretty easy to test your crank sensor by following our step-by-step instructions. This can save time and effort, while increasing your knowledge and confidence for testing components.

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