What Does A Crankshaft Sensor Do: How It Works

This article answers the question- what does a crankshaft sensor do? Crankshaft sensor is a device used in internal combustion engines to locate the position of crank and its velocity.

We shall discuss the working of an internal combustion engine first, then we shall continue our discussion further with crankshaft sensor and the working of crankshaft sensor. In later sections, we shall also read about different types of internal combustion engines.

What is an IC engine?

An internal combustion engine or IC engine is a heat engine inside which combustion takes place with the help of an oxidizer and working fuel.

IC engine converts this heat energy produced by the combustion of fuel-air mixture to mechanical energy. The main parts of IC engine include Piston, Cylinder, Crank, Spark plugs (In SI engine), crankshaft. We shall discuss more about internal combustion engines in the next section. 

Working of internal combustion engine

Internal Combustion engine is an assembly of various mechanical components that work in harmony to produce desired output.

During the intake stroke, the fuel is injected in the system. The piston is connected to connecting rod that connects piston and the crank. As the air fuel mixture is ignited, the piston moves at the bottom dead center and then comes back to the top dead. Due to reciprocating motion of the piston, the crank rotates and in turn helps the wheels to rotate.

How does a crankshaft sensor work?

A crankshaft sensor can be attached to an engine block facing towards the timing rotor or the ring gear attached on the crankshaft. The crankshaft has teeth whose positions are used to determine the actual position of crankshaft.

The sensor will keep a count of the number of teeth that have passed on the ring gear. This information is fed to the engine control unit or engine management system which then calculates the precise position of the crankshaft and decides when the switching on and off of different spark plugs.

Image credits: Tamasflex, Crankshaft sensor, CC BY-SA 3.0

Crankshaft sensor use

The uses of crankshaft sensor are not many but every use is a very significant one. The uses of a crankshaft sensor are given in the section below-

• Count the number of teeth passed and feed the information to the engine management system.
• Locate the position of crankshaft.
• The information about the position of crankshaft is then used to decide the switching on and off of different spark plugs.

Causes of crankshaft sensor failure

There are many causes of failure for a crankshaft sensor. The causes include the following-

1. Damage– Due to a sudden jerk or excess pressure on the sensor, the sensor may get damaged. Some times the heat gets inside the sensor and melts few components. Such damages lead to crankshaft failure.
2. Debris – Debris from other broken components can hinder the reading collection process and may lead to crankshaft sensor failure.
3. Faulty circuitry– When the circuit connections are not proper, the readings from sensor will not be able to reach the engine management system. The sensor will not able to find the correction position of the crankshaft drive and hence the firing order of spark plugs will be uneven leading to more fuel consumption.

How are crankshafts made?

The crankshafts are usually made of steel. The manufacturing processes may vary but commonly they are made using die forging. If the material is cast iron then they are made by casting.4

In casting process, a mould is prepared using a pattern. Then molten cast iron is added to the mould and is left for solidification. Due to solidification, the actual size of casting reduces. To compensate for shrinkage due to solidfication, risers are provided. Risers will have extra molten metal that will be served to the mould in compensation of solidification shrinkage taking place inside the casting. 

Cam shaft position sensor

Two sensors- Camshaft position sensor and crankshaft position sensors work together to determine the exact location of the crankshaft. The readings from both of these sensors help the engine management system to find the exact time to know when the first cylinder is in the top dead centre.

The principle on which a cam shaft sensor works is the Hall principle. A rng gear is located on the crankshaft which has many teeth on its circumference. The sensor counts the number of teeth passing by while the ring gear is rotating. Number of teeth that have passed are counted (due to rotation of ring gear) and due to this rotation there is a change in voltage of Hall IC in the sensor head. The voltage change is converted to a readable reading that is the position of crankshaft, this translation is done by the engine management system. 

Sensor code P0340

The camshaft sensor simply helps us to determine the location of the crankshaft.

Without the help of this sensor, the engine will not know when to ignite fuel, this will lead to ncrease in consumption of fuel and sometimes this may lead to engine damage.

Sensor code P0340 symptoms

There are different methods by which we can identify P0340 code.

Major symptoms of code P0340 are-

• Check engine light on dashboard
• Poor acceleration
• Engine stalling
• Car jerking
• Problems shifting gear
• Low fuel mileage
• Ignition problems

If you observe any of the above symptoms frequently in your vehicle then it is recommended to give the vehicle for servicing specifically targetting the sensor part.

Sensor code P0340 causes

The causes behind the setting of P0340 are given in the section below.

The following list shows the cause of P0340-

• Defective sensor
• Defective ring gear on the camshaft
• Fault in crankshaft sensor
• If the wiring inside crankshaft sensor circuit is damaged or corroded.

How serious is P0340?

An alarm alerts the user for any type of emergency situation arising in the system. There are different types of alarms depending upon the intensity of the problem occurring. If the alarm is ignored then it may lead to severe damage to the engine parts.

Initially the engine will start running erratically. The engine’s efficiency will be compromised and even mileage too. If this continue for a longer period of time and it is not treated properly then the engine can be damaged severely due to improper ignition timing.

Camshaft sensor code P0016

Another code relating to camshaft sensor is code P0016.

This is a generic OBD-II code that will indicate the camshaft position sensor about the bank 1 does not correlate to the signal from the crankshaft position sensor.

Symptoms of P0016 code

There are different methods by which we can identify P0016 code.

Some of the symptoms of P0016 code are-

• Check engine light turns on.
• Engine starts running erratically/abnormally.
• The mileage of vehicle decreases due to more fuel consumption.
• Reduction in power

Causes of P0016 code

 There are multiple ways by which this code can appear.

Major causes of P0016 are-

• Oil control valve has restriction in Oil control valve filter
• Camshaft timing is out of position.
• Camshaft phaser is out of position because of fault with phaser.

How severe is P0016

As discussed for problems pertaining to code P0034, P0016 code has similar problems.

In both the cases the engine starts stalling or running erratically. This is followed by reduction in fuel mileage. And at the end it leads to severe damages to the engine. These damages depend upon the failed part.

What to do after replacing camshaft sensor?

The camshaft sensor must be installed in correct orientation. After orienting in the correct direction, one must reset the sensor before using the vehicle.

• The procedure for resetting is very simple. The very first thing one has to do is to focus on switch ON and OFF function, these switches are connected to magnets that need to be adjusted first.
• Then we need to check engine light, crank sensor, engine block and see if there is any damage. After doing all of this, trouble codes also need to be checked by code reader and see if there is any problem or not.
• After completing the above step, we turn off all the parts that are connected to battery and start driving vehicle at 70 Kmph-80 Kmph for five minutes and then decelerate it to 50-60 kmph. This way the timing chain is changed or the sensor is reset.
• If one still faces problems while resetting then he/she should definitely consult a mechanic to perform this procedure.