How to Check a Crankshaft Position Sensor with a Multimeter

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Would you like to know more about how a crankshaft position sensor works? This article will help you understand what it is, its key functions, and so much more. So, if you’re ready, let’s dive in! 

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What is a Crankshaft Position Sensor? 

A crankshaft position sensor (or CKP sensor) is a device gauging the rotation speed and precise position of the engine crankshaft. Without this sensor, your car engine won’t work. Further, it’s installed near the central pulley in some vehicles, while in others, it’s installed in the engine cylinder block or at the transmission bell housing.

Keep in mind that a CKP sensor is accessible in all modern cars. It’s a crucial part, which has been utilized to regulate the rotational speed and position of the crankshaft. It also sends important reports to the control unit of the engine to make necessary adjustments must there be any type of failure or malfunctioning. 

Let’s dig deeper into how it works and how you change this component in case you ever require that. 

How Does a Crankshaft Position Sensor Function?

The Crankshaft Position Sensor is a device utilized to affirm the crankshaft’s rotation as the engine is moving while providing feedback in the form of data back to the main computer. The sensor is mainly located near the crankshaft, engine block, or flywheel, depending on the manufacturer’s design.

An electric pulse chart is made as the crankshaft rotates, and that changes the engine’s speed. That wavelength controls the computer output circuits like the camshaft, fuel injector pulse width, and ignition timing adjustments. The sensor also uses the reflector or stator wheel, which has been connected to the crankshaft.

Symptoms such as engine not starting, random misfiring, and intermittent fasting can be an excellent indication that a sensor is beginning to fail. Often, the sensor will begin to work again after it’s been allowed to cool down.

It might also be challenging for a few computer-run systems to locate a malfunctioning crank sensor because of other reasons, which can prevent the engine from running. These are reasons like the sudden engagement of the clutch that could cause stalling.

Keep in mind that CKP sensors use a magnetic coil situated in a plastic housing while offering an electrical connector to send data to the computer. That sensor is also utilized by the computer to collect misfiring information of the temporal deceleration of the crankshaft while the misfire happens.

The computer uses the CKP sensor when the starter is engaged to ascertain that the engine is cranking over. After the confirmation has been obtained, the computer will then deliver signals to different components like the fuel pump and the ignition system, alerting them that the engine is now ready to start. 

What are the Common Signs of a Malfunctioning Crankshaft Position Sensor? 

A failing sensor can cause many irregular problems. A vehicle would cut out or stall randomly, while others would start without any issue. The engine during wet weather might have difficulties starting and will start fine after a while.

Often, the motion speed gauge functions erratically, and the sensor could lead to a long cranking period before the engine even begins. There are also instances when the engine will crank but won’t even start at all. 

Below are some of the signs you need to look out for with a failing crankshaft position sensor. 

  • Slow response from the accelerator

Do you notice a problem with your sensor? Then one sign is that it will not deliver a piece of valid data about the cylinder’s positioning. That indicates there will be space between the computer collecting data and applying it. Hence, the accelerator falters and does not give an exact response.

  • The engine makes your car vibrate

You will find many potential speculations that there’s quite a vibration coming from the engine when it’s running. Nonetheless, it’s mostly possible that there’s an issue with the CKP sensor, especially when there’s an intense increase in vibrations.

Moreover, the vibration comes paired along with strong fuel economy and drop-in power. That will lead to the vehicle requiring more gas and power to move. 

  • Stalling or backfiring of your car

A malfunctioning CKP sensor could also cause a car to backfire and stall. Did you know that stalling is a more typical issue in a car than backfiring? That’s because of the obstruction of the crankshaft signal that can lead to the engine getting off.

On the other hand, backfiring can happen based on the time length the signals have been out and also depending on the speed of the car at the tune it happens. 

How Can You Check a Crankshaft Position Sensor? 

You can use a digital multimeter to troubleshoot your sensor even without minding whether the engine uses an inductive one or a Hall effect type sensor. Here are the steps you need to take to check a CKP sensor:

  • Ensure you remove the fuel pump or relay to deter the engine from starting. Does the engine use a distributor? You can unplug the ignition cable and set it on the engine using a jumper wire.
  • Remove the CKP sensor electrical connector and place your multimeter to DC volts with a range of 20V. 
  • Touch the meter black lead to the black wire on your strap connector. Touch the red lead to the red wire on the strap connector too. 
  • Now, turn the ignition key but do not start the engine yet. 
  • Your meter must give a data between 5-13V. If the voltage is lower or zeroes than what you anticipated, you can check the connector and wire for possible damage.
  • For the next step, turn off the ignition and insert the sensor back to the harness connector. Fix your DMM to low DC voltage to allow the reading of the millivolts. 
  • Touch your DMM black lead to battery negative and wait for a few minutes. Your DMM must show at least 200mv to 300mv. Crank your engine, and your digital multimeter must read approximately 300mv. That’s the average voltage of the signal the CKP produces.

There you have it! Now you understand what a Crankshaft Position Sensor is and how you can test it.

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