Sensor Malfunction (Here Is How To Fix)

Sensor Malfunction

A car is a complicated thing, and there are a lot of individual parts that need to be working in order for everything to run smoothly.

In this article, we’re going to help you to understand when you might be having a sensor malfunction, and how you can fix it.

There are many different sensors in a modern vehicle that can malfunction, including oxygen sensors, engine speed sensors, air-flow sensors, and much more.

If they fail, they may just need to be cleaned or repositioned, but they may need replacing.

Here below you can find a few steps on how to fix a sensor malfunction:

Step 1: Identity which sensor has failed

Step 2: Locate the sensor

Step 3: Inspect the sensor for dirt or obstruction

Step 4: Check the sensor’s position

Step 5: Investigate the wiring

Step 6: Recalibrate, repair, or replace

What Is A Sensor?

Before we get into all the different kinds that might be in your vehicle, we first want to understand what a sensor actually is and how they work.

A sensor is a term used for a device that measures inputs from the physical environment and then generates an output signal based on what has been detected. Typically, they are designed to send a signal when the element they are measuring is too great or too small.

The different kinds of inputs that sensors can measure include:

  • Light
  • Heat
  • Sound
  • Movement
  • Moisture
  • Pressure

In a vehicle, the sensors act as your car’s eyes and ears. They tell the internal computing systems, usually the Electronic Control Unit (ECU), what is going on so that the vehicle can respond accordingly – or inform you that something is wrong by flagging up a warning light.

If any of the sensors in your car malfunction, then the components that rely on that information will be working blind, and may not be able to function at all.

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How Do You Know You Have A Sensor Malfunction?

Because each sensor is different, they all can have different symptoms when they stop working.

Usually, the first thing you will notice is that a warning light will appear on your dashboard. Most sensors are designed to trigger the warning light for the system that they operate in when they malfunction – although it is not always obvious that it is the sensor that has failed.

For example, when your oxygen sensor fails, the Check Engine Light will usually turn on. There are other errors or issues that can cause this light to turn on, though, so you may need to do some investigating before you can be certain that it is the sensors that are at fault.

If a sensor fails, then you will also notice other symptoms that occur as a result of the fact that it has stopped working. These can help you to determine where the problem lies. For example, higher fuel consumption might indicate a problem with your MAP sensor, air-flow sensor, or oxygen sensor.

How To Fix Sensor Malfunction

Step 1: Identify which sensor has failed

First, you need to determine which sensor you are looking for. The warning light on your dash will be the clearest indication, but you should also consider what else may be going wrong with your vehicle.

Step 2: Locate the sensor

Once you have identified which sensor might be causing the problem, you need to physically find it. Each sensor is normally located in a pretty standard place within the vehicle, but you should still check your manufacturer’s manual to be certain.

Step 3: Inspect the sensor for dirt or obstruction

Once you have found the sensor, make sure that it is clean and free from obstructions that might be interfering with its ability to gather information.

Step 4: Check the sensor’s position

Then, make sure that it has not been dislodged or otherwise moved so that it is able to read the correct information accurately.

Step 5: Investigate the wiring

The next thing to have a look at is the wiring that connects the sensor to the other electrical components in the vehicle. Make sure the connections are not loose and the wires have not been damaged, otherwise they may need replacing.

Step 6: Recalibrate, repair, or replace

If the sensor is in the right position, it’s clean, and all of the wires are properly connected then it will need to be recalibrated, repaired, or replaced.

It is usually easiest to get a professional to help with this as it is critical that they are set up perfectly in order for them to function.

What Sensors Does Your Vehicle Have?

Modern automobiles are incredibly smart and they are filled to the brim with technology that is designed to make our lives easier and our driving experience safer and more efficient.

In order to do that, there are a lot of different sensors at work all of the time.

Not every car will utilize exactly the same sensors, but a huge number have become pretty standard for almost any vehicle.

Some of the most significant and common that you are probably relying on almost every single day include:

Air-Flow Sensor

This sensor is found inside the combustion chamber and it measures the density and volume of air that is entering the engine.

The air-flow sensor determines the correct air-fuel mixture so that the car runs at peak performance.

If it malfunctions: If this sensor fails, you might notice the engine stalling more often, or you might experience higher fuel consumption.

Engine Speed Sensor

This sensor is attached to the crankshaft and monitors its position and speed. It sends this information to the ECU so that it can calculate when to activate the fuel injectors and spark plugs to fire the engine.

If it malfunctions: Your engine may not fire at all if this sensor fails, or it may run much less efficiently.

Camshaft Position Sensor

This sensor is also there to monitor the position of the camshaft, but not its speed. Its job is to control the exhaust and inlet valves of the engine and ensure air enters the cylinders and the right time, and burnt gases leave the cylinders at the right time.

If it malfunctions: If this sensor is not working properly then you may notice lower power output or, eventually, damage to the cylinders themselves.

Manifold Absolute Pressure (MAP) Sensor

This sensor determines the difference between the pressure in the manifold and the outside pressure, to track the load on the engine. It controls when fuel needs to be relieved to adjust the internal pressure.

If it malfunctions: If this sensor fails, then you will likely notice higher fuel consumption.

Engine Knock Sensor

This sensor monitors knocking, which is when the air-fuel mixture in the cylinders ignites before the spark plugs are activated.

Knocking reduces the efficiency of your engine and can cause internal damage, so the engine knock sensor will activate a warning light to let you know there is an ignition fault.

If it malfunctions: If this sensor isn’t doing its job, then you won’t get a warning to tell you that knocking is happening, or the ignition fault warning light will be on all of the time when nothing is wrong.

Temperature Sensor

This sensor monitors the temperature of the engine. Overheating can be dangerous and it has a significant impact on the efficiency of the vehicle, so this sensor keeps track of how hot the engine is and controls the cooling system accordingly.

It will also inform you when there is a heating problem, or when there is a problem with your coolant and/or radiator.

If it malfunctions: If this sensor is not working, then the engine is much more likely to overheat, which can cause it to seize up, fail, or even become severely damaged.

Wheel Speed Sensor

This sensor keeps track of the speed at which the vehicle’s wheels are turning, and it can identify when one or more wheels are rotating at different speeds from the others.

This can indicate that the car is losing control and/or traction and is a crucial part of your Anti-Lock Braking System and Electronic Stability Control.

If it malfunctions: If your speed sensors malfunction, then you might lose traction or stability control, or your ABS might fail.

Oxygen Sensor

This sensor measures how much oxygen is in the gases coming out of your exhaust. It helps to determine the efficiency of your engine and controls elements of your engine emissions system.

If it malfunctions: If it fails, you might notice black exhaust smoke, higher fuel consumption, and skips and surges from the engine.

Parking Sensor

You might not have these on an older car, but parking sensors are designed to recognize obstacles that are in close proximity to the vehicle and alert you to their presence.

Often, the alarm will intensify as you get closer to help you avoid collisions while you are parking.

If it malfunctions: If these sensors are not working properly they might alert you to obstacles that are not there, or they might not alert you to those that are.

Why Do Sensors Malfunction?

With so many different sensors doing so many different jobs, even one malfunction can have a big impact on how smoothly your vehicle is operating. So, how and why might a sensor have stopped working properly?

When sensors malfunction, it essentially means that they are no longer able to read information accurately. This might be because they have become dirty or are obstructed, the wires may be loose or damaged, the sensors may be positioned incorrectly or improperly calibrated, or it may be that they are damaged or have developed an internal fault.

So, there are a few things that you may need to do to get the sensor up and running again.


So, what might a sensor malfunction look like and what can you do about it? There is a myriad of different sensors inside your vehicle, and they all have important jobs to do.

If one malfunction, then the system that relies on it may fail, you might notice specific symptoms, and it will typically show up as a warning light for that system on the dash.

To fix it, you may need to clean or reposition the sensor and check the wiring, but it also might need to be repaired, replaced, or recalibrated – which is usually best left to a professional.


Steve P.

Steve is an automotive technician, technical writer, and Managing Editor. He has held a lifelong passion for cars, with a particular interest in cars like the Buick Riviera. Steve is based in Boise, Idaho.

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