How Do Car Sensors Work?


There have been many significant developments in automobile technology in recent years, given the numerous advancements in the field including those like mobile connectivity and Artificial Intelligence. It is continuing to grow at a much rapid pace and is also changing how humans are using cars today.

Cars and other vehicles are more than plain objects to drive in this day and age. You can relax on your favorite music, talk to your loved ones, communicate effectively, find what you want, shop, and much more, although it is not the ideal space to do the aforementioned while driving.

Apart from this, the car engine has a unique intelligence to understand what goes on inside it. It can directly communicate with the computer contained in the car and perform the necessary action for it. But, how do they do so?

Sensors. That’s the answer to it. Sensors have covered a long journey in recent years and are playing a very essential role to ensure that your car performs and uses fuel in the most optimal way. Many other sensors do a lot more than the basic stuff and provide you with phenomenal driving experience.

Now, let’s look into what these car sensors actually do and where did they come about from.


History of Car Sensors

Before diving deep into the discussion about car sensors, let’s look back in time and understand the history and developments of car sensors.

Control System Inside the Engine

In general terms, three things are needed by any combustion engine i.e. air, fuel, and spark. These three aspects and anything else needed to balance or trigger them are handled by the control systems present inside engines.

Electromechanical or Mechanical

Historically, these systems were either electromechanical or mechanical mostly and each engine component was in charge of a certain task rather than having a centralized system to manage all. For instance, the fuel mixture and metering were handled by the carburetor, and to manage it, the mechanical distributor would trigger the spark. 

Main Issue with Control System

The main issue with these systems was that they were high maintenance. Therefore, the engine had to undergo service after covering every 35000 miles, which was the maximum that could be handled by it.

During the 1970s and ‘80s, the engine design underwent many significant changes, most of which were relevant to the emission controls which was research-intensive and needed required many changes to the design. Resultantly, the maintenance levels trickled down drastically.

Introduction of Car Sensors

The use of car sensors was among the major changes among many. Initially, they were nothing except for a simple transitional system sending information to an analog processor. As a result, the processor would perform decision making on the basis of simple algorithms that were managed by the engine functions.

Limitations in Early Sensor Systems

These early systems have many limitations, of which a major one was the fact that only predefined values could be handles by analog systems. So, any value which was not present in the programmed values gave an error and the system would simply fail. This problem intensified when the car became older and many unexpected issues started to arise as they were not programmed.

Further Changes

Further changes came about in the 1980s when the fuel injection engine replaced the carburetors and the wiring part also experienced major changes. A centralized system was needed to handle all such varying aspects like air volumes, emissions, and others among the many – this was when car sensors came out.


What Are Car Sensors?

Advanced Systems Handling Various Processes

These are intelligent systems controlling various systems like coolant levels, temperature, emission levels, oil pressure, and a lot more. They can accept a great range of values, process them appropriately, and also determine the right level or mixture for each of these aspects.

This information can easily be communicated from the sensor to computers, so they are reported to the driver when they are missing something. The sensors are continuously working starting right from the time you power your car until you turn the ignition off. Sending real-time signals to computers is also possible as these sensors are always monitoring and the driver can be well aware of what’s happening at that moment. Hence, no delay occurs and it is easy for both the driver and system to take any corrective action immediately.

Recent Advancements and Modern Features

In recent advancements, car sensors have become the central part of the car’s system and are not used only to control various aspects vital for the car’s smooth performance, rather they handle almost everything from the internal temperature control of the car to head and tail light operations.

Some modern-day cars also have the option for drivers to make the most out of the mobile connectivity, giving exact information to drivers for anything they need. for instance, the GPS systems provide a route to a destination from the current location of the car.  With more advancements coming in every day, the time is not far when each aspect of the car will be taken care of by sensors.


Types of Car Sensors

Following is a list of prominent car sensors with their functions among the many that are available:

Mass Air Flow Sensor

The air density and volume taken in by the engine is calculated by this sensor. It ensures that only the right fuel amount required for the given optimal driving conditions is taken in by the engine. The sensor holds more importance because the car may end up consuming more fuel than required or the engine may stall if the sensor fails.

Engine Speed Sensor

This sensor monitors the crankshaft’s spinning speed where it is attached. Crankshaft controls fuel injection in the engine and is hence very important, as no one wants excessive fuel entering their engine. The chances of your car stopping suddenly are also reduced by this sensor.

Oxygen Sensor

The oxygen amount present in the exhaust pipe is calculated by this sensor, on the basis of which is can be determined if the car is burning lean or rich. The car will consume excessive fuel and may even jer or idle often if the sensor fails.

Manifold Absolute Pressure Sensor or MAP Sensor

Engine load is monitored by this sensor, which calculates the difference between manifold and outside pressure, making sure that the engine can take fuel according to the change in this pressure.  Efficient fuel consumption is also ensured by this one like many others.

Spark Knock Sensor

This sensor ensures that fuel combustion is happening smoothly and that no detonation is occurring unexpectedly as it can be dangerous for the car, failing the basket and breaking the breaks or even damaging the rod bearing significantly. These aspects may be very expensive to fix, so the sensor saves a lot of trouble for the car engine and yourself. 

Fuel Temperature Sensor

This one monitors fuel temperature constantly to ensure optimal fuel consumption. Changing inflow levels can damage other parts of the vehicle, so this sensor ensures that only the right temperature fuel goes in the engine for it to work smoothly.

Voltage sensor

It is a very important sensor as it manages the idling car speed and ensures it is increased and decreased as per need.

Most of the sensors mentioned above are included in the car already, while others may have to be purchased separately. You can decide for yourself the sensors you need the most. The best way is to conduct some research on various car sensors, which are relevant for your use especially when you are investing in extra bucks to get them installed. Talk to experts if you are unsure so they help you in choosing only the valuable ones, and you save up some on spending unnecessarily.


How do Car Sensors Work?

Most modern-day cars have smart sensors installed in them that monitor other sensors as well, and the driver is not required to have knowledge about all the intricate details about the sensors’ working.


Multiplexing has allowed this to happen. Multiplexing is a process where a microprocessor consolidates the wires present in each area of your car and ensures that it does not get out of your control. For instance, the driver door module is responsible for all the inputs and outputs in that particular area, alone and also communicated with other related sensors for its operation.

Module Communicating with Other Sensors

Another interesting question arises from here, i.e. how does the module know about which sensor should it communicate with?

A simple example will illustrate this work. Taking the example of a driver door module again, when the driver presses the button to lower their window, an action is performed, a data packet is communicated to the car’s communication bus.

This information is directed to another module that energizes the power window’s motor, and the communication is hence quite simple. All the communication happening between the various sensors and their controlling modules pass via one of the input or output wires of communication bus present in your car’s central system.

Use of Multiple Modules and Sensors

The scalability is increased drastically with such a setup as multiple modules and sensors can be added to the car, and there will be no impact on the communication in any way. Moreover, there’s no need to alter the wiring system, communication bus, or anything else in order to ease out communication between the new and old modules.



To summarize, car sensors are a great step up to enhance the car’s usability, life, and condition. Even better, its implementation and scalability are very easy as smart sensors powered by modules are now being used in most modern cars. This simplified setup eases out the process of adding in more modules, and the future holds many exciting innovations for car owners as manufacturers are coming up with novel modules with the latest functionality in each release, transforming driving into a hassle-free, enjoyable experience.