Automobile Problems

Why is My Speedometer Not Working?

Why is My Speedometer Not Working?
Written by Autofot
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Most time we hear the complain that my car speedometer is not working. Before we can address this subject matter, it is important that we explain what speedometer is, and how it works. With this explanation you will know about the speed you are driving at? Well, the speedometer is the instrument to look at when you want to know the instant speed readings. Safety on the road depends on many factors and maintaining the right speed limit is one of them. So, when the car speedometer not working, you don’t know whether you are driving slow or fast. We can also say it is an instrument which provides the driver with instantaneous readings of speed. Traditional speedometers used gears and wires to determine speed, while most modern vehicles use speed sensors for the same. Common problems include, a faulty sensor, bad wiring, or dial malfunctions. Troubleshooting speedometer problems mostly call for a replacement of the speed sensor or cable, depending upon the vehicle. As it were, there are some factors that could make car speedometer not to work.


Fuse could be one the reason why your car speedometer is not working. The fuse may cut off wire thereby make the speedometer not working. There will need to perform a thorough examination of the fuse to see if it is blown off or cut fuse. If yes is the answer, there will be a need for replacement of fuse. Your auto professional will also look at all of the wires that run from the speed sensor to the speedometer- and check for any damage.

Electrical Break down

Electrical issues can break down speedometer. A wire may cut off or got burnt. There are a lot of things that could cause these things mentioned.

There are many reasons that could cause a speedometer not to work. The most common reasons do involve an electrical issue or even a problem with the speed sensor. Both issues can affect other areas of your vehicle -that are outside of your speedometer. Will also look at other factors that can cause your speedometer fail to work?

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Engine Control unit

The ECU which stands for the Engine Control Unit is a center for lots of engine activities. Another way to think of the ECU is the brain of the car commonly known as Brian box. Your ECU helps to monitor and control lots of activities of the engine- including your vehicle’s speed. So, your engine control unit may give incorrect readings if there is an issue in the unit. On this case a careful diagnosis should be carried out.


Wrong wiring is another reason for the vehicle speedometer not work. Wrong wiring can short circuit the system thereby impose a problem to  wire. Lots of times, a wire can simply short. Sometimes, this results in a fire or a fuse that is blown. This is a problem for older cars.

Broken Speed Sensor 

A speed sensor serves lots of purposes including indicating and displaying the speed of the vehicle, helping to regulate the fuel and flow, regulating the ignition timing, and helping to operate the vehicle’s cruise control. A speed sensor that has collapsed may stop your speedometer from operating or  not functioning properly. You may also take note that your vehicle is not running as it should. There is even a chance that your “check engine light” may illuminate, alongside your malfunctioning speedometer.

Sometimes, computer issues can cause a speedometer not to work. You may be enduring a vehicle that has had some water damage, or even some electrical short circuited somewhere. Regardless of the issue, you never want to operate car without a working speedometer.

Worked Engine

When we talk about my speedometer is not working, there are some potential factors such one, the car engine being worked on by auto mechanic. Some electrical wires are being disconnected by the auto mechanic on the process of working on the engine or dropping the engine down for overhauling. Because he is not Electrian, he will find it difficult to connect the wires in proper places. This will therefore, impose some mistake that will make the speedometer not work. So, It is important that whenever you are doing such an engine work you call Electrian to standby to do his work to avoid mistake that will cause damages. Alternatively as soon the mechanic finishes it’s own work, the Electrical man takes over all the electrical installations to avoid failure.


A simple visual check can also give decent results in diagnosing issues with a speedometer. Apart from the speed sensor, the corresponding connectors and wiring have to be checked for symptoms of degradation or damage. One can also inspect cluster functions if one suspects irregularities. In some cases, drivers find that the speedometer needle is jumping, or a failure is becoming an intermittent issue.

If you have found that the speed sensor of your vehicle is defective, you must replace it immediately. This simply involves taking out the damaged hold-down fastener of the sensor, extracting the component from its bore, and installing a new one.

Wiring faults are a bit harder to fix and involve finding the damaged portion of the affected circuit. This is when a replacement pigtail or harness can be bought. Alternatively, circuit repair may be possible in particular cases.

If the speedometer of your vehicle is completely defective, the instrument cluster has to be removed. This generally involves the removal of certain dash components along with their associated hardware. After that, you can buy a new/remanufactured instrument cluster. If you’re running low on funds, get the damaged cluster rebuilt. Further diagnostics must be conducted in the event of a suspected ECU failure. Make sure to refer to the manufacturer’s guidelines for that. Though computers like these can fail from time to time, issues of this nature are somewhat rare.

Can I Self-service My Speedometer

First of all, it’s necessary for you not to start working on what you do not have an atom of knowledge about. Not having technical no-how of any car component, means that you don’t have to start working on it whenever there is a problem on the car. Otherwise you end up damaging things in the car.

If you notice that your vehicle’s speedometer doesn’t seem to give you an accurate reading or is not working at all, then you have an issue on your hands that a mechanic may need to remedy- unless you are a mechanic. Many times, it takes a change of wiring or computer components, to fix a speedometer. So, if you are equipped to handle this, then go for it. Otherwise, you need to visit a trusted mechanic for a proper diagnosis and fixing of your faulty speedometer. The sensors of your speedometer may need to be re-calibrated. So, you may need to visit an auto shop for computer diagnosis and possible fixing.

Having a properly calibrated speedometer is vital as you drive on the roads.  It helps you to put on check things like  tire wear, tire temperature, tire pressure, vehicle load, tire diameter, wear and tear of the tires, and even differential gearing can all affect the readings that a speedometer offers. For just about all of the issues that prevent a speedometer from working properly, you may need the assistance of a mechanic to help you fix it.

Is it Ideal to Drive My Car with Bad Speedometer?

It is not advisable because of so many dangers involve. A vehicle with a bad speedometer can be quite unpractical as well as quite unsafe. When you don’t know your speed, then you put yourself at a greater risk at getting a ticket or citation by local police. You really won’t have much of a leg to stand on, as you attempt to fight the charge of speeding, because you don’t have a working speedometer. Additionally, not being able to determine your speed, also increases your potential for a vehicle accident. You shouldn’t drive a vehicle with a malfunctioning speedometer, till you can get into a car shop for a speedometer repair.

Scanner Use

A good Auto mechanic will first begin with a machine diagnosis. This will begin by examining the vehicle with a code scanner or reader so that any error codes can be revealed and read. The mechanic will also check to see if the “check engine light” is on. The auto professional will connect to the vehicle’s Engine Control Unit so that he or she will have a better understand of what vehicle components have failed. In every repair, the mechanic will clear out all trouble codes of the vehicle generated by the ECU with a code scanner/reader. Before leaving, they will take the vehicle on a test drive and check for the proper functioning of all systems. The speedometer should be functioning okay again.

Underneath Check

If your auto professional has reason to believe that the speed sensor is experiencing any kind of failure, she or he will go underneath the vehicle and locate the precise location of the sensor- as well as any adjoined wires. The mechanic is on the hunt for any kind of superficial damage to the component. The mechanics will then take off the old speed sensor and install a new one.

The Need for a New ECU

There would be need for a new ECU the auto tech will replace it. A simple reset of it may not work when it comes to getting the speedometer to function properly and may serve as a temporary fix.

Once the mechanic installs a new ECU, she or he will take the key and turn it to the “Auxiliary” position. This will give the new ECU to turn, and begin its process of vehicle system management. Once the vehicle is turned on, it should begin to make proper adjustments so that it can offer optimum performance to the driver.

Clearing of Any Trouble Codes 

With all repairs, including that of a malfunctioning speedometer, the auto tech will clear out any trouble codes that may have been created due to the ECU’s code scanner. Before sending you on your way, you and your mechanic will probably take a test drive of the car, to ensure that you have a properly-functioning speedometer.  Before leaving, you and your mechanic will take a test drive the vehicle to ensuring that you have a working speedometer as well as working components surrounding the speedometer.

Cost To Fix A Speedometer Not Working? 

The cost to fix your speedometer that isn’t working will depend on the make and model of your car. Generally, repairs to a speedometer can run between $200 and $500, depending on the amount of time and energy and how qualify the personnel is to the repair. Your speedometer repair may be covered under warranty. So, it may be to your benefit to take it to your dealership for a repair that will cost you nothing. If you do have the skills to fix it yourself, then you are looking at a repair that is a lot lower in cost.

Can I Use My Phone as a Speedometer Instead?

GPS is a common feature in all modern smartphones. As a result, your device can accurately recognize its own location and decrease car insurance in addition to its speed of travel. A few innovative minds have realized this niche and explored it, developing speed-tracking applications to help you keep track of location and speed without the amenities provided by your vehicle.

In the event of a failure of the speedometer, a speed-tracking application can be used to keep tabs on the speed of the vehicle. Fortunately, many of these apps are free to download and use, so it’s best to download one immediately the moment the speedometer starts displaying signs of failure.

However, it’s important to note that these kinds of apps are not 100% accurate. Therefore, only consider these applications as a fall back option, not permanent. Your primary concern should be resolving the speedometer’s issue.


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About the author


Autofot is a website that blogs on the importance of taking good care of our automobiles. Little things that are ignored matter the most, hence we try to educate car owners and other different auto owners on how to go about taking care of their cars with little or no cost.

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