Car Sensors and Their Functions Explained

Automobile technology is one of the most evolved, and the cars we have at the moment bear this out.  The result of technological development in car manufacturing is various components that make driving and car maintenance hassle-free.

Among the essential parts that most new-age cars sport is the car sensor. They play a crucial role by notifying you of issues within the car’s systems. It helps you pinpoint the part with a problem and saves time when it comes to repairing and maintaining 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 car sensors to give this essential car part the appreciation it deserves in auto-engineering and car mechanics.

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 applications were going mainstream at this time, and they featured in several sectors, such as banking and industry. Vehicle systems at that time were mechanical and electromechanical, and car components worked on these principles.

There was no centralization of the duties performed by the car parts, though each contributed to the engine’s efficient operation. The problem with this system was that the car parts wore out fast and pushed maintenance and repair costs to the ceiling. Research introduced computer systems to detect errors in the vehicle and help identify engine problems more easily.

The dawn of computer systems also provided the foundation for redesigning engines to accommodate a computer system. These units helped coordinate the vehicle’s systems. This was around the mid-80s, and the first sensors started appearing.

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 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 as triggers that turn them on and initiate the info relay process.

A good example is the car’s pressure sensor. The pressure sensor relays a 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.

Any fault notification demands your attention and aids in the prompt maintenance of your car. Other vehicle sensors work the same way, with some, such as temperature sensors, triggering changes while doing so. When they detect a significant rise or drop in the vehicle’s temperature, they send the info to the processor, which issues 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, 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

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 indicates 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 helps the engine computer unit 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 balanced mixture for efficient vehicle performance. The sensor is usually mounted on the intake manifold, with its tip exposed to detect the temperature of the incoming air. 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

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 measures both pressure and temperature, two variables the engine control unit uses 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 in 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

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 similarly to the mass airflow sensor to determine the air mass flow rate. The rate determined from the calculations aids the control unit in determining the perfect fuel-to-air ratio, which balances the air-fuel mixture.

5. Oxygen Sensors

Oxygen sensors have been a mainstay in the industrial scene for almost five decades, an invention by Dr. Gunter Bauman. These sensors help determine the 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 and regulated gas emissions. It comes in handy today, 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. There are several sensors used in diesel engines, and you can also find them prominently in petrol-operated vehicles.

The knock sensors detect vibrations resulting from the ‘knock’ caused by incomplete combustion. They send vibration signals to the engine processor, which then corrects anomalies to ensure efficient burning of the air-fuel mixture.

7. Crankshaft Sensors

The crankshaft sensor, also called a crank sensor, is an electric component present in both diesel and petrol engines. This sensor monitors the crankshaft’s position and rotational 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 camshaft. Electric signals from both sensors go to the engine management system and help control various variables to ensure a smooth ride.

If there is any deviation from normal in the camshaft’s position and rotation rate, the sensor sends 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 with 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 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 is 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 fuel-focused sensor 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 measures the pressure in the fuel tank, which aids in leak detection. Should there be a leak, pressure changes, and the sensor relays signals to the main processing unit in the engine. This turns on the check engine light so you can 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 helps detect changes in speed and ensures the change occurs as required.

12. NOx Sensor

NOx sensors are important for controlling emissions and protecting the environment. These sensors are high-temperature electric devices that detect various forms of nitrogen oxides.

A lot of research is still ongoing to develop NOx sensors that help curb nitrogen oxide emissions. These compounds have many negative effects, such as smog, acid rain, and health complications.

The sensors detect the amount of these compounds emitted through the exhaust. 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 each. Exhaust temperature sensors are among the most advanced technologies for controlling emissions, and most new-age automobiles feature these components.

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

In diesel engines, the exhaust temperature sensor reads the heat of the diesel particulate filter. In this case, it helps establish whether 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 for regulating engine performance and improving the automobile’s 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 these signals, the control unit can regulate fuel delivery for optimal combustion of the air/fuel mixture.

15. Throttle Position Sensor

The throttle position sensor is usually mounted on the throttle body. It monitors how far the throttle blade opens, 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, acts like a valve.

The sensor checks 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 using transaxle output and relays the information to the vehicle’s engine computer. With this information, 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) detects the presence of water in the fuel tank. The sensor detects water levels in the tank through the electrical conductivity difference between 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 dashboard.

18. Tire Pressure Sensor

Tire pressure is an essential element for 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.

To help you keep tabs on this variable, we have tire pressure sensors positioned in the pocket created by the wheel and tire. They measure the tire’s air pressure and transmit the values via low-frequency radio. The signals are sent to 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 with torque, and non-contact sensors can measure this change. 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 with braking, steering, and 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 helps detect the heat in the transmission fluid. It transmits the collected data 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 level comes courtesy of the oil level sensor.

The sensor uses magnetism, with a magnetized sealant moving up and down the oil chamber tube. A magnetic reed switch turns off a switch when there is a change in oil levels. Consequently, the switch completes a circuit, notifying you 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.

Fuel level sensors are widely used in fleet management, where you can connect them to a GPS. This helps you track fuel use and refuels, which can help you detect 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 acts as an accelerometer, detecting 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 leaks. The sensor has a port that measures pressure, and when it drops, it sends a signal 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 notes any difference from 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 to obstacles, especially when parking in reverse.

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

Electromagnetic car parking sensors rely on motion: their alarm goes off when you approach 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 that require attention.

You can install as many as you want, as long as you are sure of their relevance to your car’s efficiency. With a simple mechanic’s tool 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.