Function & Working of a Crankshaft Position Sensor

The crankshaft is one of the most important components of an engine that converts the pistons’ reciprocating motion into a rotational movement, making your car move. The crankshaft position sensor monitors the speed and location of rotation.

These materials will help lubricate your motor to run smoothly and more efficiently. Furthermore, they provide real-time data to the Engine Management Unit (EMU) and use it for timing fuel injection and ignition as needed, which greatly helps the engine work even more efficiently on less fuel. One of the major observations regarding this is that having a crankshaft position sensor can help you avoid misfires, starting problems, and stalling.

Explore this article to learn how a crankshaft position sensor works, the signs of a failing sensor, and much more.

How Does a Position Sensor Work?

Sensing Mechanism

When you look closely at the crankshaft, you will see a strong magnet placed nearby. Around the crankshaft, steel pins or pegs are set up at even intervals. This magnet always creates a steady magnetic field. Once the engine starts and the crankshaft begins to turn, the steel pins move within this magnetic field. This motion changes the magnetic field, creating an alternating current (AC) signal.

This signal is then sent to the Engine Management Unit (EMU). The EMU uses this data to figure out how fast the crankshaft is turning and its exact position. This helps the EMU control the timing for fuel injection and ignition, ensuring the engine runs efficiently.

Performance Adjustments

An engine’s performance comes from how its internal components run within set speeds. The crankshaft position sensor tracks the motion of the crankshaft. The onboard system, therefore, tunes the engine’s performance with adjustments made in real time upon receiving that information. When you push the accelerator in, the computer can still adjust the engine’s speed based on data from that sensor. It compares the speed of the crankshaft at all times to the optimum and adjusts it accordingly to be smooth and provide the best energy.

Symptoms of a Failing Crankshaft Position Sensor

  • Engine Misfires: The sensor informs the ECU about the crankshaft’s position and speed. This information is important to the ECU because it helps advance the spark plug timing and fuel injection. When the sensor is bad, the ECU gets bad information, and misfires occur when the fuel and spark do not happen at the right moment.
  • Starting Problems: Regarding the operation of the ECU during engine start-up, the unit located on the crankshaft position sensor signals ignite spark plugs and injectors. Without this signal, the engine will not receive the spark or fuel it needs to start, and the car can stall or have trouble starting altogether.
  • Stalling: Like misfires, a bad sensor affects the pulse timings of fuel and spark, which are essential in the combustion of fuel in the engine. This can make the engine behave or rather run poorly, sputter, and stall, especially during idling, which requires a command over the efforts of the air-fuel mixture.
  • Check Engine Light: A Vehicle Control Unit senses several things at all times, including the crankshaft position sensor. If it identifies an issue with the sensor signal, it switches on the Check Engine Light to warn the driver.

Difference Between Camshaft and Crankshaft Sensors

The camshaft positional sensor estimates the position of the camshaft and additionally contributes to the specialty of fuel injection time. Similarly, the crankshaft sensor monitors the position and the pace of the crankshaft to make the engines fire in the right manner. These two sensors are very effective and they complement each other depending on the status of the engine.

However, the camshaft sensor proves to be specialized for targeting the camshaft which is entirely different from the sensor that targets the crankshaft. Therefore, they execute different operations as far as the management of the engine is concerned.

Camshaft Position Sensor Symptoms

Just like a crankshaft sensor, the Camshaft position sensor also presents symptoms when it is not working as it is supposed to. If these symptoms are present, then one could be having a hard time executing some of the basic operations like having a rough running engine, low mpg among others or even having difficulties in igniting the fuel in the vehicle. Therefore, if one is broken, you should track these two sensors on this matter and look for help.

Why The Crankshaft Position Sensor Is Important

The crankshaft position sensor is an important component of automotive engines you should not take lightly. It helps to advise the ECU concerning the corrections to the time of the engine with precision which is the right way for the fuel to burn and there are lesser emissions or else the engine of your car will not run smoothly, it will utilize a lot of fuel and will emit more to the atmosphere.

How to Maintain Your Crankshaft Position Sensor

Proper maintenance can prolong the service of your crankshaft position sensor. Here are a couple of tips:

  • Regular Check-Ups: Make sure to check the sensor during any routine maintenance.
  • Clean connections: Ensure that the connections to your sensor are clean and properly fixed.
  • Avoid Overheating: Try to keep your engine cool to prevent overheating.


The crankshaft position sensor is crucial for engine efficiency, preventing misfires and stalling. Regular check-ups and clean connections can ensure it functions well. If this sensor fails, your engine may run poorly and use more fuel. Keep it maintained for a smoother, more efficient drive.

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