Car crankshaft position sensor on an isolated white background.

Like in other industries, technology in the automobile sector has significantly evolved over the years. While you could count the number of sensors installed in old car models with one hand, the cars of today have numerous sensors sending signals to the vehicle’s electronic control unit (ECU) to ensure that the car is running efficiently. 

Some models come equipped with more sensors than others, depending on what the local jurisdiction requires manufacturers based in that area. For example, due to the need to reduce air pollution, most modern models would have detectors designed to measure nitrogen oxide (commonly known as NOx sensors).  You can also browse around here for the various engine models with these kinds of sensors. 

Even though sensor types can vary from one car model to another, some sensors are common enough that you’d find them in almost any model regardless of car brand. Here’s a quick rundown on the most common sensors, and what makes them so important. 

  • The Fuel Temperature Sensor 

Fuel temperature plays an important role in making sure a car engine runs efficiently. Fuel needs to be at the right temperature for the engine to burn it properly. Warm fuel is less dense and burns quicker, while cold fuel is the opposite. This can affect the engine’s fuel efficiency and its power output.

The fuel temperature sensor makes sure that there is an optimal amount of fuel injected into the combustion changer. It does this by sending a signal to the ECU that tells if the engine is too warm or too cold. If the temperature is too high, the ECU will increase the density by injecting more fuel to the combustion cylinders. If it’s too cold, the ECU limits the amount of fuel that goes into the combustion area to help. If this sensor fails, you may notice a check engine light and experience a significant decrease in your car’s fuel efficiency. 

Manifold absolute pressure sensor

  • The Mass Air Flow (MAF) Sensor 

The mass air flow sensor is located between the engine’s intake manifold and the air filter and is vital for an engine’s electric fuel injection system. This sensor monitors the volume and density of air that gets into the engine. By determining the pressure and temperature of the airflow, it sends signals to the engine control unit, which ensures the proper ratio of air to fuel mixture for optimum combustion. 

If you have a faulty MAF, you may experience poor fuel economy or difficulties when starting the car. Additionally, a failed MAF can result in uneven power delivery, resulting in the car suddenly jerking when cruising at average speeds. Also, your engine light would be on when the MAF is faulty. 

  • The Crankshaft And Camshaft Sensors 

The crankshaft and camshaft sensors are two separate sensors that work together to keep the engine running consistently. These two sensors are designed to detect the position of the crankshaft and camshaft. If one of these components is off-position, the sensors can send a signal to the ECU, which then controls the ignition timings and fuel injection to help normalize the sensors

A failure of any of the two can result in your car emitting white smoke or stalling. Additionally, you may experience difficulties when starting your car, excessive engine vibrations, and a reduction in engine performance. 

  • Engine Coolant Temperature Sensor (ECTS) 

While your engine runs, the energy produced by the combustion is converted to power and heat. Most of the heat is expelled through the vehicle’s exhaust system. However, some of it remains within the engine, warming the engine up and causing some components to expand and create friction. To prevent this, coolant runs through the engines and draws heat away. It then flows to the radiator to be cooled off, ready to draw more heat, keeping the engine sufficiently cooled. 

The ECTS temperature sensor monitors the coolant’s temperature to see if there’s enough of the coolant running and if it is properly drawing and shedding heat. The ECU uses this information to adjust such functions as turning the electric fan on or off, fuel injection, and ignition timing. Together with the engine temperature sensor, the signal from the ECTS helps get a more accurate reading of the engine temperature. This info is then sent to your dashboard’s temperature gauge. 

A faulty ECTS can result in a wrong engine temperature reading and overheating. Additionally, you may get a rough engine sound when it’s idling. Other symptoms of faulty ECTS can be poor fuel economy and reduced engine performance. 

  • The Manifold Absolute Pressure (MAP) sensor 

A sensor that’s a crucial feature for internal combustion engines, the MAP sensor helps measure the pressure inside the engine’s manifold. The MAP calculates the difference in and outside the manifold from the engine’s load. As the engine’s load fluctuates relative to the barometric pressure, the MAP sensor sends the results to the vehicle’s ECU. The ECU uses data from the MAP sensor to determine the optimum air-fuel ratio for perfect combustion. 

If you have a faulty MAP, you may experience uneven acceleration, engine stalling, and reduced fuel economy. In other locations, you may hear of engine load sensor or pressure sensor used interchangeably for a MAP sensor. 

  • The Engine Knock Sensor 

Sometimes, the air-fuel mixture can be uneven and result in a misfire when you turn on the engine. This results in engine knocking and can damage other parts of the engine. The knock sensors help monitor the engine’s air-fuel combustion process during ignition. Engine knocking causes vibrations, and it’s these vibrations that the knock sensors pick up to send signals to the ECU. The ECU, in turn, adjusts the air and fuel ratio to obtain the optimum combustion mixture. 


Car sensors are essential for keeping the car running optimally and, if there’s a failure, help narrow down the cause of the problem for easier repairs or part replacements. That said, acquainting yourself with some of these common indicators can be the difference between a smooth ride or a trip to the mechanic.

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