A Bad Speed Sensor Needs Immediate Attention

While driving down a scenic route, we may forget the speed of the car at times, or we may be in a hurry to reach somewhere and forget to monitor the speed of our vehicle. Thanks to the modern sensors, now we can stay within speed limits, and we don’t have to worry about warnings and speeding fines from the cop. Speed sensor systems have proven to be a great software tool for drivers these days. But what will happen if it stops functioning properly? 

What Is The Speed Sensor All About?

Today’s cars come equipped with sensitive systems and help drivers navigate the crowded streets and highways with much ease. They can detect issues with the tires, engines, and the fuels and oils in the vehicle.

One of these sensitive sensors is the speed sensor. Which is programmed to regulate the car’s speed and affects the car mileage, fuel consumption, and how the car idles. It can check the car’s speed and convey the data to the transmission system when gears are changed, and above all, it is very significant for the cruise control mechanism.    

We can see that the speed sensor impacts all these factors, and its malfunction will lead to unregulated driving, and the car may not only cross the speed limits, but it may also hamper the safety aspect of the car and passengers. 

Symptoms Of A Bad Speed Sensor

The car speed sensor is a sensitive and small indicator and is part of the transmission system. Its software measures the rotation of a toothed wheel or a gear kind of device on the shaft that again is part of the transmission.

The computers of the car, or the control modules, receive information from this sensor in the form of low voltage signals.

When these signals don’t reach the engine and controls, they don’t have any proper data to execute proper controls and adjustments that the car may constantly need.

The vehicle’s cruise control also depends on the data coming from the speed sensors. The car’s safety is compromised when the computer system does not have the required data and properly execute controls. 

● One of the symptoms and effects of speed sensor malfunction is that the automatic transmission will face issues. The operation may show delayed or difficult moves from one gear to another. The gear may also malfunction as it cannot perceive the speeds correctly. This happens as the transmission control module, and power steering cannot accurately detect the gear shift timings.  

● You may lose control of the cruise control in your car. When the transmission system does not receive any sensor signals, cruise control will be disabled without that information.

● Without the sensor, the speedometer may also not give accurate readings. You cannot realize the speed of driving of your vehicle or when you cross the speed limits on any kind of road without the speedometer on the dashboard. Whether speeding in a city or on highways, all roads have their speed limits, and you cannot know the right speed without the coordination between the speed sensor and the wheel. The speed that you see on the dashboard may most probably be wrong. 

● The torque converter clutch follows a programmed speed, and without the signals from the sensors, it cannot apply the clutch correctly. This means the engine and transmission do not have a connecting link. This, in turn, may lead to fuel-guzzling and maybe some heat damage to the transmission.  

● The dashboard will light up with the check engine light. This may signal many issues related to the engine, and on inspection, you can detect that the speed sensor is the reason for the signal. It may also trigger other warnings as the other control systems will not work properly. 

Why Does The Speed Sensor Malfunction?

The speed sensor itself may be damaged from inside and give improper signals. You can test its electrical integrity and replace it if needed. Another reason for the malfunction of the speed sensor may be that its magnetic part is covered in debris from the different fluids in the engine and transmission area.

This magnet is important for the signals to come from the toothed wheel to the sensor, and if it does not connect properly, the signals will also not be conveyed to the speed sensor. 

The sensor may be damaged or broken due to an external impact. With long-term use and age, all the devices may break or malfunction. The car also needs periodic maintenance, and skipping it may also lead to the failure of some of the most critical and sensitive sensors. 

Experts Advise Not To Drive With A Faulty Speed Sensor

If you are always a careful driver, it is still possible to drive without the speed sensor. But in today’s time, it is neither safe nor advisable to drive with a malfunctioning speed sensor in the car.

These sophisticated systems are interconnected and impact the functioning of the other software programs and the car mechanism itself. Also, it is a safety hazard as you will not even realize it when you cross the speed limit.

In addition, the efficiency of the gear shaft, mileage, fuel injection, engine, etc., will be compromised if the sensor is malfunctioning. 



Cars come with a speed sensor that helps the engine and transmission regulate the speed mechanism of vehicles. The cars’ technical system has functional parts that align and work together. Even if one of these malfunctions, the system loses the connectivity and data, which is more important to run the car smoothly. 

There are many symptoms of a malfunctioning speed sensor. If you notice a flashing sign on the dashboard, you can check all the engine parts and find the real reason.

Even otherwise, you can check the speed sensor if you feel some drag while driving or cannot execute the cruise control mechanism. You can check the speed sensor if you know how to detect the fault or take it to a mechanic as soon as possible.

Liam Dare

As CEO of ReplicarClub.com, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.