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Different Sensors Used in Modern Cars and Their Functions

Team AckoFeb 9, 2023

Modern vehicles are packed with technology to make them more efficient and safer to drive. In this electronic era, cars can have multiple Electronic Control Units (ECUs) that control different functions of a vehicle.

Most vehicles have one primary ECU that manages all the engine functions to ensure it is running smoothly; some can have more depending on how much technology is packed into them.

The ECU gets all the relevant information it needs to make decisions from various sensors around the vehicle. To put it simply, if we consider the ECU as the brain of the vehicle, the sensors can be regarded as its sensory organs, which feed it information to comprehend what is happening around it.

In this article, we will look at the most common types of sensors in a car and their individual functions.




Here's a list of the most common sensors found in vehicles at a glance:



Oxygen Sensors

Measure the presence of oxygen in the exhaust system.

Mass Air Flow (MAF) Sensor

Measures the volume of air in the engine intake.

Engine Oil Level Sensor

Measures the level of engine oil in the engine.

Engine Oil Pressure Sensor

Monitor oil pressure in the engine.

Coolant Temperature Sensor

Monitors the temperature of the coolant circulating the engine.

Coolant Level Sensor

Monitors the level of coolant in the engine cooling system. 

Air Intake Temperature Sensor

Measures the temperature of the air in the air intake.

Manifold Absolute Pressure (MAP) Sensor

Measures pressure difference between the outside and the engine manifold.

Boost Pressure Sensor 

Monitors the amount of pressure between the turbo and the engine.

Engine Knock Sensor

Monitors engine knocking and adjusts ignition timing accordingly.

1. Oxygen Sensors

The ideal air/fuel ratio for an internal combustion engine to run efficiently is 14.7:1. This means that in order to burn one gram of fuel, there needs to be 14.7 grams of air in the combustion chamber. 

Oxygen sensors, also known as O2 sensors, monitor the presence of oxygen in the exhaust pipes of vehicles. This information is relayed back to the ECU, which then alters the air/fuel ratio to ensure the engine is running as efficiently as it should. 

2. Mass Air Flow (MAF) Sensor

The mass airflow sensor is a part of the vehicle's air intake system that measures the volume of air entering the intake. The ECU uses this information to determine the amount of fuel that it has to inject to obtain optimal combustion. It is usually located between the intake filter and the intake manifold. 

If the MAF sensor on a vehicle goes bad, the ECU will not know how much fuel to inject into the combustion chamber, resulting in poor engine performance. 

3. Engine Oil Level Sensor

Maintaining the right amount of engine oil in an engine, as per the manufacturer's recommendation, is crucial to prevent catastrophic engine damage.

Inadequate amounts of engine oil can lead to decreased levels of lubrication within the internal components of an internal combustion engine (ICE) which results in a lot of wear and tear. This increased friction between the moving parts can raise the engine temperature to such an extent that an engine can seize altogether. 

This sensor is usually mounted on the side of the oil pan and is linked to the engine oil warning light you see on the dashboard of most vehicles. If this light comes on, check your engine oil levels immediately. 

4. Engine Oil Pressure Sensor

All ICE engines use forced lubrication systems to circulate and ensure that the engine oil circulates to every nook and corner of the engine to enable smooth operation and prolong its longevity by preventing metal-on-metal contact. 

The engine oil pressure sensor is usually located at the bottom of the cylinder head and is also connected to the engine oil warning light on the dashboard. On certain vehicles, it can be linked to the check engine warning light as well. 

5. Coolant Temperature Sensor 

If you have some knowledge of basic physics, you must be aware that heat is the killer of efficiency. All modern engines have a robust cooling system to maintain optimal engine temperature for maximum efficiency.

These systems circulate coolants to take away the heat from the engine and then pass them through the radiator, which cools down the coolant again. This happens in an endless cycle as long as the engine is running. 

If the coolant gets too hot, the sensor sends a signal to the ECU, which then lights up the coolant temperature warning light on the dashboard. If this happens, you should stop immediately to prevent the engine from overheating and eventually seizing. 

6. Coolant Level Sensor

As discussed earlier, coolants are circulated through the engine to prevent it from overheating. The coolant level sensor is located either at the bottom of the radiator or inside the expansion tank and triggers a warning light in case the coolant level drops below a certain threshold. 

You should only use coolants recommended by the manufacturer to ensure optimal cooling performance and mitigate any chances of engine overheating. 

7. Air Intake Temperature Sensor

The temperature of the air coming into the engine can affect the vehicle's performance. Cold air is denser and thus contains more oxygen molecules and vice versa.

The air intake temperature sensor is located between the intake filter and the intake manifold, just as the MAF sensor discussed earlier.

In some vehicles, the air intake temperature sensor is built into the MAF sensor, and together they let the ECU decide the amount of fuel to be injected to keep the engine running as efficiently as possible. 

8. Manifold Absolute Pressure (MAP) Sensor

The MAP sensor's primary role is to send crucial pressure data in the engine manifold. It calculates the difference in pressure inside and outside the engine manifold to ensure that the engine always receives adequate fuel regardless of the pressure changes outside the engine. 

This sensor is usually located on top of the intake manifold or in the intake track in engines that are not naturally aspirated. A faulty MAP sensor can result in a drop in mileage, with the engine surging or stalling frequently. 

9. Boost Pressure Sensor 

Boost pressure sensors are only found in vehicles that have forced induction, i.e. cars that are either turbo or supercharged.

Their primary function is to read the pressure difference between the turbo or the supercharger and the engine. The ECU then uses this info to inject the right amount of fuel for optimal engine performance. 

These sensors are usually located inside the intake pipes of an engine and can lead to reduced performance if they stop working properly.

Since the ECU is not able to provide adequate fuel for the amount of air entering the engine, you may also have trouble starting the engine if the sensor fails. 

10. Engine Knock Sensor

Engine knocking can seriously damage an engine. Knocking occurs when the air-fuel mixture ignites before the ignition phase causing an imbalance in the 4-stroke engine cycle.

The knock sensor monitors the engine for unusual vibrations that occur due to uneven detonation. The ECU then uses this information to correct the ignition timing, thus preventing knocking and keeping the engine running smoothly. 

A faulty knock sensor can lead to reduced power and efficiency and, if unchecked, can cause serious damage to an engine. 

Summing It Up

While this is just the tip of the iceberg when it comes to the various types of sensors in a car, you now know what the basic and the most important sensors in modern vehicles are. Sensors go a long way in letting you know when something is failing in a vehicle, which lets you take corrective action in time. 

Just as sensors can help prevent catastrophic failures in vehicles, a good insurance policy can also prevent your finances from taking a hit in the event your vehicle is involved in an accident and needs costly repairs. ACKO has various motor vehicle insurance plans with bespoke payment plans to match all your coverage needs - check them out today.


Here are commonly asked questions about the different sensors used in modern cars and their functions.


 How many sensors do modern vehicles have?

On average, most modern vehicles can have around 70 sensors. Certain tech-laden vehicles with ADAS and other safety features can have up to 200 sensors in one vehicle. 

What other areas of a vehicle are sensors used in?

Apart from the engine, sensors are used in a vehicle's air-conditioning system to gather vital information such as the vehicle's current speed, distance travelled, and tyre pressure. They are also used in safety systems, such as anti-lock braking systems and traction control systems. Airbags, for example, have impact sensors that detect an impact and trigger airbags when necessary.

What are the advantages of having so many sensors in vehicles?

Sensors let you know when something is not right with your vehicle. This enables you to fix small issues before they lead to more serious failures, which can have deadly consequences. They also make sure your engine is running optimally to ensure maximum efficiency across multiple driving conditions.

What are the disadvantages of having many sensors in a vehicle? 

Sensors are sensitive pieces of technology that do fail over time and can be quite expensive to replace. That being said, the benefits they offer do outweigh this one disadvantage.

What can cause a car sensor to fail?

Every mechanical or electronic object is bound to fail at some point in time. However, sensors either tend to fail due to wear and tear over time or if they overheat due to any reason.

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Disclaimer: The content on this page is generic and shared only for informational and explanatory purposes. It is based on several secondary sources on the internet and is subject to changes. Please consult an expert before making any decisions.


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