Car Sensors and Their Functions

Automobile technology is one of the most evolved, and the cars we have at the moment lay bare as evidence.  The result of the technological development in car manufacturing is various components that serve to make driving and car maintenance a hassle-free engagement.

Among the essential parts that most new-age cars sport is the car sensor. It plays a crucial role in the car in notifying you of an issue within its system. It helps you narrow down to the part with a problem and saves on time when it comes to repairs and maintenance of your vehicle.

They also help in controlling various aspects, such as fuel intake and heat. To a pro in auto-engineering, it is an agreeable fact that the sensors have streamlined the overall ownership and handling of automobiles.

There are different types of sensors used in cars, and as an automobile enthusiast or mechanic, you need to know about them. They are embedded in the engine, and each of them performs a specific function. With a sensor-equipped vehicle, you have the assurance of efficiency on the road.

Let us look at the history of the car sensor to give this essential car part the appreciation they deserve in auto-engineering and car mechanics.

car sensors

The History of Car Sensors

Car sensors came sometime after the golden age of motor vehicle engineering, which many pundits put from the mid-50s to early 60s. It was during the 1970s, when auto-manufacturing took a new shape, with heavy inspiration from the technology of that time.

Computer application was going mainstream at this timeframe, and they featured in several sectors, such as banking and industries. To understand the situation at that time when it came to vehicle systems is that they were mechanical and electromechanical, and the car components worked through these principles.

There was no centralization in the duties that the car parts carried out, though each brought its weight for the engine to work efficiently. The problem with this system was that the car parts wore out fast and pushed maintenance and repair costs to the ceiling. Research brought about means to incorporate computer systems in the car to detect errors in the vehicle to help with the easier detection of engine problems.

The dawn of computer systems additionally provided the foundation for the redesign of engines for them to accommodate a computer system. The unit would help in the coordination of the vehicle’s systems. This was around the mid-80s, and the first sensors started featuring in the scene.

The early sensors were not that effective, though they still performed their duties. Further technological development improved their effectiveness, and they started being common in cars manufactured in the 1990s. By the turn of the millennium, many drivers appreciated the role of the sensors, and cars started coming out of production halls with sensors already embedded with a central processor in the engine.

Right now, they are an essential component of vehicles, and the car sensor list you will see later on in the article will introduce you to some.

how many sensors are in a car
Image Source: Car From Japan

How Does A Car Sensor Work?

As a mechanic looking forward to a successful practice in your workshop, you need to understand how automotive sensors work. As their name hints, they work like sensory organs and send important information to the engine. They detect changes in stimuli, which act like a trigger that turns them on and initiates the info relay process.

A good example is the car’s pressure sensor. The pressure sensor will relay some voltage depending on the pressure it registers. If the pressure levels go past a certain limit, it sends the info to the central processor in the engine through a wire connection or new-age wireless means. The engine will, in turn, notify you through an alarm or a light going off in the dashboard.

The notification of any fault demands your attention and aids in the prompt maintenance of your car. The other vehicle sensors work in the same way, with some, such as temperature sensors affecting change while at it. When they detect a significant rise or lowering of the vehicle’s temperature, they send the info to the processor, which carries a parallel command to correct the issue. The air conditioner can turn on or off, or air inlets will open or shut to regulate the heat to the required levels.

Different Types of Sensors

Any serious car and auto-engineering enthusiast has or at one time in their lives had the question of how many sensors are in a car? To answer this question, we provide a list of sensors that your vehicle’s system may sport.

1. Coolant Temperature Sensor

Coolant Temperature Sensor
Image Source: Amazon

Starting off the car sensor list is the coolant temperature sensor. It is also referred to as the engine coolant temperature sensor (ECTS), and its function is to measure the temperature of the coolant or antifreeze in the cooling system.

This component works in tandem with the car’s electrical control unit, and it gives you a hint of how much heat is coming from the engine. The sensor’s information goes to the control unit, and if the temperature is not at optimum levels, the unit will initiate changes to correct the deviation.

Some of the changes include fuel injection rate, ignition timing, and switching on and off the electrical fan.

2. Intake Air Temperature (IAT) Sensor

The intake air temperature sensor is a crucial component of the car as it helps determine and monitor the temperature of the air entering the engine. The temperature monitored aids the engine computer unit to make the right measurements when balancing the air-fuel mixture.

Colder air is usually denser than hot air, and it will need more fuel to maintain a balance of the mixture for the efficient performance of the vehicle. The sensor is usually mounted on the intake manifold, with its tip exposed to help detect the temperature of air getting in. It sends this information to the engine computer to make the necessary changes in fuel injection to meet the air-fuel balance.

3. Mass Airflow Sensor

Mass Airflow Sensor

The mass airflow sensor is another air sensor installed in the vehicle. The sensor determines the mass flow rate of air entering the engine. It takes note of both pressure and temperature, two variables that the engine control unit focuses on for fuel injection.

There are two types of mass airflow sensors; the hot wire and the vane meter. Both of them have an intake air temperature sensor on their structure, mostly for cars manufactured after 1996.

The mass airflow sensor works accurately when paired with an oxygen sensor, another sensor we will look at.

4. Manifold Absolute Pressure Sensor

Manifold Absolute Pressure Sensor
Image Source: Amazon

The manifold absolute pressure (MAP) sensor is common in internal combustion engines and gives information on engine vacuum pressure. The info goes to the engine control unit and helps calculate air density. The calculations provide a clear picture of the mass airflow sensor.

In short, the manifold absolute pressure sensor works in the same way as the mass airflow sensor when looking at the result to give the air mass flow rate. The rate determined from the calculations aids the control unit in coming up with a perfect ratio of fuel injected, which balances the air-fuel mixture.

5. Oxygen Sensors

oxygen sensor

Oxygen sensors have been a mainstay in the industrial scene for almost five decades, an invention by Dr. Gunter Bauman. These sensors help determine proportional oxygen in either liquid or gas.

The oxygen sensor is located in the emission system and keeps the emissions in check. The result is top-notch performance as well as the regulated emission of gases. It comes in handy in the present times when several lobby groups are pushing for reduced pollution from automobiles.

These sensors started being common in auto-engineering after the 1980s. Most cars have at least one oxygen-detecting device, with the new models having up to four for efficiency.

6. Knock Sensors

Knocking is one of the common engine problems in injection engines. It results from improper combustion of the air/fuel mixture, and you will notice a knocking when you turn on the ignition. They are some of the sensors used in diesel engines, but you can also find them prominently in petrol-operated vehicles.

The knock sensors take note of the vibrations resulting from the ‘knock’ due to incomplete combustion. It sends the vibration signals to the processor on the engine, which will, in turn, correct the anomalies to ensure efficient burning of the air and fuel mixture.

7. Crankshaft Sensors

The crankshaft sensor also goes by a crank sensor; It is an electric component present in both diesel and petrol engines. This sensor monitors the position and the crankshaft’s rotating speed, an important part of the vehicle.

The engine management unit uses the information from the sensor to control a variety of engine variables such as fuel injection and ignition timing. It works together with the camshaft sensor to improve the car’s overall efficiency.

8. Camshaft Sensor

As earlier introduced, the camshaft sensor, also known as the camshaft position sensor, works together with the crankshaft sensor to determine the exact position of the crankshaft. Electric signals from both sensors go to the engine management system and help control various variables to ensure a smooth ride.

In case of any deviation from the normal, when it comes to the position and rotation rate of the camshaft, the sensor will send signals to the central processor. Most of the time, the processor will relay the messages to the dashboard to notify you of the anomaly.

The camshaft and crankshaft sensors are essential for maintenance as they prevent further strain on a poorly positioned crankshaft.

A problem of either the camshaft or crankshaft sensor may present itself through the emission of white smoke from the engine.

 9. Fuel Temperature Sensors

A significant part of the car’s motion relies on fuel injection; hence, it is an activity that should be ideal at all times. Several sensors are dedicated to fuel injection in internal combustion engines, one of them being the fuel temperature sensor.

The fuel temperature sensor detects the temperature of fuel just as its name hints. The main point of focus lies in the fuel density as hot fuel is less dense than cold fuel. The difference in density values affects the amount of fuel injected.

This sensor helps regulate fuel uptake, which subsequently controls emissions and consumption.

Read: Low Fuel Light Comes on When Tank Is Full Causes and How to solve it

10. Fuel Tank Pressure Sensor

Another sensor that focuses on fuel is the fuel tank pressure sensor. It is part of the fuel tank assembly, and you will find it embedded on the top or sides of the fuel tank. It is a crucial component of the evaporative emission control system, which prevents vapors from the gas tank from escaping to the atmosphere.

The sensor takes note of the pressure in the fuel tank, which aids in the leaks detection. Should there be a leak, there will be changes in the pressure, and the sensor relays signals to the main processing unit in the engine. This action turns on the check engine light for you to make the necessary checks to get to the root of the problem.

11. Voltage Sensor

The voltage sensor is another common sensor that you will find in vehicles. This component manages car speed, especially the idling speed.  It is helpful in the increase or decrease of speed and ensures the change of this variable takes place as required.

12. Nox Sensor

Nox sensors are important sensors when it comes to controlling emissions and conserving the environment. The sensors are high-temperature application electric devices that help to detect the many forms of nitrogen oxides.

A lot of research is still ongoing in the development of Nox sensors to help curb the emissions of nitrogen oxides to the environment. These compounds have a lot of negative effects, such as smog, acid rain, as well as health complications.

The sensors detect the amount of the compounds passing out through the exhaust fumes. If the levels are high, the management system will initiate processes to reduce these gases.

13. Exhaust Temperature Sensor

The exhaust temperature sensor features both petrol and diesel-run engines and performs a different function in either of them. The technology of exhaust sensors is some of the most advanced when it comes to controlling emissions, and most new-age automobiles feature these components.

In petrol engines, this sensor prevents the vehicle’s elements, such as the turbocharger and catalytic converter. If the sensor notes high temperatures in these components, it relays an electric signal to the engine control unit to lower the heat, mostly by reducing pressure.

In diesel engines, the exhaust temperature sensor reads the heat of the diesel particulate filter. In this case, it helps in establishing if the conditions are ideal for self-cleaning of the filter.

14. Boost Pressure Sensors

These engine elements feature mostly in turbocharged cars, and they provide information on air pressure and air/fuel ratios. This information is essential when it comes to the regulation of engine performance and improves the automobiles’ overall performance.

They also control the boost level in the intake chamber of supercharged engines or those with a turbocharger. This part measures the absolute pressure and air density before the throttle valve and sends the signals to the control system. Using the received signals, the control unit can regulate the fuel amount for the best combustion of the air/fuel mixture.

15. Throttle Position Sensor

Usually mounted on the throttle body is the throttle position sensor. It oversees how far the throttle blade opens, a phenomenon determined by how far you step on the accelerator pedal. The throttle’s position affects air intake into the engine’s manifold, and in a way, it acts similarly to a valve.

The sensor checks on the throttle’s position and the speed of its opening and closure. Like any sensor, it sends voltages to the engine’s computer system, which determines the fuel injection rate to balance the air-to-fuel ratio.

16. Vehicle Speed Sensor

Another one of the many types of sensors used in automobiles is the vehicle speed sensor. It measures wheel speed focusing on transaxle output, and takes the message to the vehicle’s engine computer. With the information on the wheels’ speed, the control unit regulates parameters related to vehicle speed. The variables include ignition timing, air intake, and the air-to-fuel ratio among others.

17. Water In Fuel Sensor

One of the problems you may encounter with your car is contaminated fuel. There are several contaminants, and the common one is water. Your vehicle cannot run on water as fuel, and you may notice telltale signs such as poor acceleration, ignition problems, and knocking.

The water in the fuel sensor (WiF) is the device that detects the presence of water in the fuel tank. The sensor detects the water levels in the tank through the electrical conductivity difference of either petrol or diesel and water. If there is excess water, the sensor transmits the data to the ECU and then to the dashboard, which is noticeable by the check light on the notification.

18. Tire Pressure Sensor

Tire pressure is an essential element when it comes to having a smooth and safe ride. When the tire pressure decreases, it affects your vehicle’s performance, and in extreme conditions, it may lead to an accident.

In helping to keep tabs on this variable affecting the tires, we have the tire pressure sensors positioned in the pocket created by the wheel and tire. It measures the tire’s air pressure and circulates the values via low-frequency radio. The destination of the signals is either the ECU or the dashboard, where the readings are in pounds per square inch (psi).

19. Torque Sensor

The torque sensor, also known as the torque transducer, measures and records dynamic torque. Measuring dynamic torque is difficult, and this sensor overcomes the challenges by using a magnetic domain to condition the rotating shaft.

The magnetic properties of the domain vary depending on the torque, and non-contact sensors can measure the variable. These are magnetoelastic sensors and are standard in racecars, typical automobiles, and aircraft.

As a mechanic or a car owner, you need to know that there are two types of this sensor; rotary and reaction. They measure dynamic and static torque, respectively.

20. Transmission Fluid Temperature Sensor

Transmission fluid is a crucial element in an automobile’s transmission system. It helps in braking, steering, and also in lubricating parts of this system. The transmission fluid has a high boiling point, and when exposed to excess heat, it may lead to the transmission system’s failure. Failure can result in poor steering and braking, slow response, and at times a burning odor.

The transmission fluid temperature sensor comes to your aid in detecting the heat of the transmission fluid. It transmits collected to the dashboard, compelling you to act to correct the problem.

21. Oil Level Sensor

Oil is a must-have utility for your car to move perfectly. It helps in lubrication, and you need to check its levels regularly. An ideal way to keep tabs on your vehicle’s oil limit comes courtesy of the oil level sensor.

The sensor applies the properties of magnetism, where a magnetized sealant moves up and down the tube of the oil chamber. A magnetic operation reed turns off a switch when there is a change in oil levels. Consequently, the switch will complete a circuit leading to notification of the fault on your dashboard.

22. Fuel Level Sensor

The fuel-level sensor plays a role in determining the amount of fuel in the tank at any particular time. It provides a hint on fuel refills, drainage, and the remaining volume.

The fuel level sensors have significant use in fleet management, where you can connect them with a GPS. Here, you can keep tabs on fuel use and refuels, which helps you know if there is any fuel theft.

23. Airbag Sensors

Airbags are important car parts when it comes to upholding safety. During impact, they deploy and cushion passengers, preventing injuries. The airbag sensor is a key element in airbag technology and plays a role as an accelerometer, which detects the car’s deceleration.

It collects this information and sends it to the airbag control unit, which will activate the airbag in case of an impact.

24. Brake Fluid Pressure Sensor

The brake fluid pressure sensor is part of the automobile’s braking system and helps detect the braking fluid’s pressure. The braking fluid operates ideally at certain pressure levels, and a slight deviation may affect its performance.

A deviation in pressure indicates a problem in the system, such as poor-quality brake fluid or leakages. The sensor has a port that measures the pressure, and when it drops, it sends the message as electric voltage to your dashboard.

25. ABS Sensors

The ABS sensor is also known as the wheel speed sensor, and it records the wheels’ speed and sends the info to the ECU. The wheels may vary in speed, and the sensor takes note of any difference from the normal.

The sensor resembles a toothed ring with a coil-over and a magnet to capture and transmit it to the engine control unit.  The message sent to the control unit helps prevent the brakes from locking on the wheels during motion.

26. Car Parking Sensor

Parking sensors help in parking by detecting obstacles and notifying the driver of their presence. The sensors use either ultrasonic systems or electromagnetic properties to alert you of obstacles, especially when in reverse parking.

The sensor shoots out pulses, with a control system measuring their return intensity to approximate the distance from the obstacles. If it is too proximal, a sensor alarm goes off faster as a warning.

Electromagnetic car parking sensors rely on a motion where their alarm goes off when approaching a barrier if you stop, the sounds reduce in intensity.

How to find faults in cars and also reset faults away? Do OBD scanning. ( YouTube )

Final Words

Above are the various types of car sensors that you need to know about as a car owner or a car repair professional. They are important systems in the car and help notify you of anomalies in the car systems which require attention.

You can install as many as you want as long as you are sure of their relevance when it comes to your car’s efficiency. With the simple mechanic’s tools set, you can install the systems on your own. Be sure they are functioning well so that you do not miss warning signs of any damage to your automobile.


Hi there, I am R. Hasan Tito, a mechanic, and owner of this website. My friend and I created this website to share our knowledge, expertise, and experience with our fellow mechanics' community and car users. I am a specialist and certified automotive mechanic (Both Heavy Commercial and Private Cars). I worked as a Mechanic and Mechanic Supervisor for over fifteen years at Global Rebound Automotive companies - Toyota, TATA, BMW, Nissan, TVs, and Others. Now, I enjoy my new role of leading a team of automotive experts (in their respective fields) and publish new content on a regular basis on my website and social media.

7 thoughts on “Car Sensors and Their Functions

  1. Hey Carol, several things could be the root cause of the problem. There’s no one-fits-all answer.

    It could be a faulty sensor, worn plugs, fuel system issues, or anything else.

    I did advice you contact your mechanic to come check the vehicle at home.

  2. Hey Masango, thanks for reaching out.

    Generally, it is likely to be a failed mass air flow sensor (MAFS). The Mass Air Flow Sensor (MAF) measures how much air enters the intake. To operate with the airflow, it sits between the air filter and the throttle body. So if you are wondering why you have to press the gas pedal to get the car started, the MAF sensor may be to blame.

    Another thing I will recommend you to check is the fuel pump. There’s a high chance the fuel pump pressure is weak. If the pump is weak, it could be the cause.

    Your mechanic may disagree that the pump is not at fault because most pumps only malfunction when the engine is hot. Still, persuade him to check the pump. Or, check it yourself if you are a DIYer type. While checking the pump, also check and replace the fuel filter if necessary. The fuel filter in the 2001 Toyota Corolla is placed inside the fuel tank.

    Even if the fuel filter is severely clogged, do not forget to replace the pump.

  3. Good evening my toyota corolla 2001 model, doesn’t want to start with a key only will need a bit of accelerator, but once the temperature has move from cold it starts with ease, it does this only in the morning, I don’t what can be the challenge, many mechanics are unable to trace the fault, probably you can assist, kind, rgds

  4. Maybe spark plugs issue, but stalling might vaccum leak or dirty throttle body. If the sensor is faulty so engine check light will come on, and you need to code the reader for identifying the faulty sensors.

  5. Hi, I have a v8super charged maloo Ute and it has started to stall and the ideling has gone from 1 to zero and back up to 1 a few times then stalls.i am in lock down in Melbourne .I thought maybe my sparkplugs have oiled up due to lack of high speed driving but reading this I think it may be a sensor .can you please give me some advice as I am a single mother.

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Posts