A Guide to Car Sensors: The Most Commonly Found Sensors in Modern Vehicles

By ced •  Updated: 02/10/23 •  6 min read

Cars nowadays are equipped with a large number of sensors, all of which are used to make your driving experience safer and more enjoyable. Most cars have at least several, if not all of the following sensors: mass air flow sensor, engine knock sensor, engine speed sensor, camshaft position sensor, manifold absolute pressure (MAP) sensor, throttle position sensor, voltage sensor, oxygen sensors, temperature sensor, carbon monoxide sensor, parking sensor and rain sensor. Let’s talk about all of these sensors and what their specific purpose is.

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A Guide to Car Sensors

Mass Air Flow Sensor

The mass air flow sensor is responsible for reading the amount of air that enters your vehicle’s engine and then sending this information to the ECU, which will use it to determine how much fuel needs to be injected into the cylinders. The more air that is entering the engine, the more fuel is needed; therefore, this sensor has a very important role in determining your car’s power output as well as its fuel economy.

Engine Knock Sensor

This sensor is used to detect engine vibrations caused by excessive heat or poor lubrication. When the engine knock sensor detects these vibrations, it will send a signal to the ECU which will then adjust the fuel injection timing so as to reduce or eliminate the engine knock. This makes for smoother running and lessens wear on internal parts of your vehicle’s engine.

Camshaft Position Sensor

This is one of the most important sensors in modern cars because it contains information about how far each camshaft has rotated during every single revolution of the crankshaft. This information is then used by the ECU to determine how much fuel needs to be injected, at what pressure and at what time. This sensor is so important that most cars these days are equipped with two of them: one on each side of the engine block.

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Manifold Absolute Pressure (MAP) Sensor

This is a sensor that measures the amount of pressure in the intake manifold. It does this by sending out an electrical signal whenever it detects a change in pressure; this signal is then received by the ECU which uses it to determine how much fuel needs to be injected into each cylinder. The MAP sensor is used in conjunction with the throttle position sensor as well as other sensors that measure exhaust gas temperature and engine coolant temperature.

A Guide to Car Sensors

Throttle Position Sensor

As the name implies, this sensor measures the amount of throttle opening; therefore, when there’s more throttle opening (i.e., the accelerator pedal is pushed down), the sensor sends out a higher voltage signal which is then used by the ECU to determine how much fuel needs to be injected into each cylinder. This sensor works in conjunction with the MAP sensor as well as other sensors that measure exhaust gas temperature and engine coolant temperature.

Voltage Sensor

This is a very basic sensor that’s responsible for sending out a signal whenever it detects an increase or decrease in voltage. Most cars these days are equipped with at least three of these: one in the battery, one in the ignition system and one in the starter motor. In addition, there are also voltage sensors in other systems such as the air conditioning system, power steering system and so on.

Oxygen Sensor

This is a sensor that’s used to measure the amount of oxygen in the exhaust gas. The more oxygen that’s present in the exhaust, the less fuel needs to be injected into each cylinder; therefore, this sensor has an important role in reducing emissions as well as increasing fuel efficiency. This sensor works in conjunction with the air/fuel ratio sensor which measures the amount of air entering the engine.

Temperature Sensor

The temperature sensor is one that detects changes in temperature, usually exhaust gas temperature. It works by sending out a signal whenever there’s a difference between its current reading and the last one; this signal is then used by the ECU to determine how much fuel needs to be injected into each cylinder.

Throttle Body Sensor (TPS)

This is one of the most common sensors that you’ll find on a vehicle; it’s used as a switch, detecting when the accelerator pedal has been pushed down and sending out a voltage signal whenever this happens. Throwing out the TPS will cause your car to idle poorly and possibly stall, so be careful when working with this sensor.

Carbon Monoxide Sensor (CO)

This is a very important sensor that’s used to detect Carbon Monoxide in exhaust gases. If there’s too much carbon monoxide in the air entering the engine, it means that either there’s an excessive amount of unburned fuel or there are cracks in one or more components inside the engine block. The CO sensor sends out a voltage signal whenever it detects high levels of carbon monoxide in the air; this signal is then used by the ECU to determine how much fuel needs to be injected into each cylinder.

Parking Sensor

The parking sensor is used to detect obstacles when you’re parking your car. It’s a very basic sensor that sends out a voltage signal whenever it detects an object within ten to twenty centimetres of the rear bumper; this signal is then used by the ECU to determine how much brake pressure needs to be applied in order for the vehicle to stop as quickly as possible without damaging the obstacle.

A Guide to Car Sensors

Rain Sensor (Rear Wiper)

Nowadays, most cars are equipped with rain sensors which make driving in rainy conditions much easier. These sensors detect when the wiper blades are on and will turn off the headlights automatically; they’ll also turn off the rear wiper if there’s already water running down the window.

If one of the sensors becomes faulty or gives inaccurate readings, it’s important to diagnose the problem as soon as possible so that it can be rectified before any damage is done to your vehicle. Sensor locations vary depending on model and year, but in general, they’re located in similar places on every vehicle.

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