What Does a Crankshaft Sensor Do? (Explained)

This sensor measures the crankshaft position. Despite its size, it is everything. Engine control units (ECUs) use this information to track crankshaft movement. Do you know when to inject fuel and when to time it? Thank you, little guy, for keeping everything on track. Can we live without it? You might have trouble starting your car. There is also the possibility that it will not run properly. Sensors play an important role in engine performance, and if one fails, the engine will perform poorly. Do you keep it in good condition? You won't regret it.

What is a Crankshaft Sensor?

It is one of the most important components of your vehicle's engine management system since it controls the crankshaft position. In addition to monitoring the crankshaft's position, it also monitors its speed. Imagine it as a watchdog for the engine, ensuring everything is running smoothly. An engine control unit (ECU) receives information from the sensor about the crankshaft's rotation. What is the significance of this? It's simple. In order to ensure smooth and efficient engine operation, the ECU controls crucial engine functions, such as ignition timing and fuel injection.

It is possible for modern vehicles to use magnetic inductive sensors, Hall-effect sensors, or optical sensors to measure the crankshaft rotation. Sensors for crankshaft position detection use different methods, but they all serve the same purpose: giving precise information about how the engine is working. Crankshaft sensors prevent engines from knowing where the crankshaft is in their rotation, resulting in poor performance, hard starting, and potentially even engine failure. Moreover, you can also learn about How to Test ECU with Multimeter. 

Types of Crankshaft Sensors

Magnetic Inductive Crankshaft Sensor

There are many types of magnetic inductive sensors in vehicles, but the most common is the magnetic inductive sensor. Electromagnetic induction is the mechanism that drives it. A magnet and a coil form a magnetic field around the crankshaft's toothed wheel, which generates a voltage. As a result of the teeth of the wheel, the magnetic field fluctuates and induces a current in the coil. It is used by the engine control unit (ECU) to calculate the speed and position of the crankshaft based on this current. With its reliability, simplicity, and cost-effectiveness, it is ideal for everyday use in the automotive industry.

Hall-Effect Crankshaft Sensor

There is a difference between a Hall-effect sensor and a normal sensor. Detection of crankshaft position is based on magnetic fields. Crankshaft rotation is caused by a magnetic field generated by a permanent magnet inside the sensor. This causes the voltage to fluctuate. The Hall-effect sensor detects this change, which is then transmitted to the ECU. There are a number of advantages to using hall-effect sensors, including their accuracy and durability. Due to their durability, they are ideal for long-term, reliable performance.

Optical Crankshaft Sensor

It uses light to detect the crankshaft's position through an optical sensor. The crankshaft is equipped with a light emitter and a light detector. An emitter and detector are separated by a disc with slits or patterns, allowing light to pass through. An ECU receives this light signal and interprets it into data. High-performance engines often feature optical sensors, though they are generally more expensive and more sensitive to contaminants, such as dust and oil.

How Does a Crankshaft Sensor Work?

In order to determine crankshaft position and rotational speed, the crankshaft position sensor continuously monitors the crankshaft. The process goes like this, step by step.

In the initial stages of the engine's start, the crankshaft rotates, which is detected by the sensor. There are several types of sensors that generate a signal based on the rotation of the crankshaft, namely magnetic inductive sensors, Hall-effect sensors, and optical sensors. Magnetic inductive sensors generate a voltage when the crankshaft's toothed wheel passes through the coil of the sensor. Hall-effect sensors detect changes in the magnetic field caused by the crankshaft passing a magnet by generating voltages. A crankshaft pattern determines the position of an optical sensor using light.

An Engine Control Unit (ECU) receives a signal from the sensor once the crankshaft position is detected. ECUs adjust the timing and injection of fuel based on this data. In order to control the timing of the fuel injectors and the ignition of the spark plugs with precision, the ECU must know the exact position of the crankshaft. With this synchronization, the engine runs efficiently, consumes less fuel, and performs better.

Crankshaft sensors provide real-time data to the ECU in order to maintain engine performance. This sensor prevents the engine from misfiring, from starting, and from performing efficiently without it. Crankshaft sensors ensure smooth, reliable performance by keeping all engine parts in harmony.

Test a Crankshaft Sensor

It is straightforward to test a crankshaft position sensor, but it requires precision and the right tools to do so. To make sure the sensor works properly, follow this step-by-step guide:

Tool Gathering

Ensure you have the right testing tools before you begin. Here are the things you'll need:

• Multimeter (preferably one with voltage measurement and resistance measurement capabilities).

• An error code scanner (optional, but helpful).

• A wrench or socket for removing the sensor if necessary.

Check for Error Codes

To find out whether the crankshaft sensor is faulty, check the car's ECU for errors. If the Check Engine Light is illuminated, use a diagnostic scanner tool to find out what the code is. There are several codes associated with bad crankshaft sensors, including P0335, P0336, and other related ones. While it's not a guarantee, this confirms that it's the sensor that's malfunctioning.

Locate the Crankshaft Sensor

Engine block or the timing cover typically houses the crankshaft sensor, which is located near the crankshaft. Getting to it may require removing some components, so know where it is before you begin.

Visual Inspection

Check the area visually before testing. If the sensor or its connector appears damaged, examine it for frayed wires, corrosion, or oil contamination. Faulty readings can be caused by dirty or damaged sensors.

Test with a Multimeter

Testing the sensor will be done with your multimeter next. The type of sensor you use (inductive or Hall-effect) will determine whether you need to check resistance or voltage. Testing each type is as follows:

• Inductive Sensors: Choose the ohm setting on your multimeter. Test the sensor's resistance by measuring the resistance across its terminals. Sensors that measure too high or infinitely are probably faulty. It is usually recommended that the resistance be within a certain range, as specified in the service manual of your vehicle.

• Hall-Effect Sensors: Change the multimeter's mode to voltage or frequency. Test the sensor by cranking the engine. During crankshaft rotation, the sensor should send a consistent voltage or pulse signal. It is possible that the sensor is malfunctioning if there is no signal or a fluctuating signal.

Check the Voltage Output

Depending on the type of sensor, you can test its voltage output. If you want to test the sensor's signal wire, connect your multimeter to the wire while revving the engine. Signals should fluctuate with the engine's revolutions if the sensor is working. The signal from a Hall-effect sensor should be a square wave or digital. Crankshaft teeth passing by inductive sensors should produce varying voltages.

Test the Wiring

If you're having problems with the sensor, but the wiring appears to be working, check the wiring. Make sure the sensor and ECU are connected by using a multimeter. Even a good sensor may not be able to send its signal to the ECU if there is a loose wire or broken connection.

Replace the Sensor If Necessary

Upon failing these tests, the sensor should be replaced. Replace the sensor by disconnecting the wiring, removing it, and then reinstalling it. The ECU should then be cleared of any error codes and the system should be reset.

Applications

Engine Timing and Performance Control

Crankshaft sensors are essential for controlling ignition and fuel injection timing. Engine Control Units (ECUs) receive real-time data from the sensor as it tracks the crankshaft's position. By using this data, the ECU can optimize ignition timing and fuel delivery, resulting in an efficient engine, reduced emissions, and improved performance. It would be impossible for the engine to know where the crankshaft is without this sensor, resulting in poor performance and misfires.

Preventing Engine Misfires

Engine misfires are also prevented with crankshaft sensors. The sensor ensures a smooth spark plug firing by providing accurate information about the crankshaft's rotation to the ECU. The engine may misfire if the timing is off, resulting in poor fuel efficiency, increased emissions, and possible damage. This sensor ensures that the crankshaft is running smoothly and prevents misfires.

Enhanced Fuel Efficiency

Modern vehicles strive to improve fuel efficiency, which can be enhanced with the crankshaft sensor. As the engine's rotational data is fed to the engine's ECU, it is able to adjust injection rate and fuel consumption based on the engine's speed and load. It optimizes combustion by supplying the engine with the right amount of fuel. Therefore, emissions are reduced and fuel efficiency is improved.

Wrapping Up

Although the crankshaft position sensor might be small, it plays a critical role in the operation of your engine. Basically, it ensures that everything is on time, including the timing of the fuel, ignition, and so on. The result would be faulty ignition, poor performance, and a hefty fuel bill without it. Also, it helps you diagnose engine problems. Your engine light might be coming on because of this sensor. Make sure you keep an eye on it. It's not a good idea to wait until you have a bigger problem. Simply take care of your engine, and it will thank you. Learn more on our website about electronics.