4 Common Causes of a Faulty Speedometer

Your speedometer might not seem like the most important part of your vehicle, but it's something you're probably going to be looking at multiple times every time you're in the driver's seat. It's crucial for keeping you safe and ensuring you don't accidentally exceed any speed limits, but unfortunately, the speedometer can suffer issues that affect its performance. This might be down to the speedometer itself or to another part of your vehicle, and any issues should prompt you to seek expert attention as soon as possible.

Here are just four common causes of a faulty speedometer.

1. Worn Speedometer Cable 

One of the most common causes of a faulty speedometer is a bad speedometer cable. These cables do wear out over time, and a failing one will naturally impact the performance of your speedometer. If the cable has worn out, you're likely to notice your speedometer needle jumping up and down without cause or only working intermittently.

2. ECU Problems

ECU stands for Engine Control Unit. This is essentially the computer that's housed in your car's dashboard, and sometimes software issues or communication problems between the ECU and your speedometer can affect the speedometer's performance. If this is the case, you're most likely to notice your speedometer not working at all, instead remaining at zero no matter how fast you happen to be driving.

3. Instrument Cluster Issues

It isn't just the ECU that affects what you see on your dashboard. You may experience anything from blown fuses to more serious electrical issues in the instrument cluster itself. When that happens, the speedometer is likely to stop working as it should. Additionally, you may notice issues with other parts of your instrument cluster, such as the fuel gauge.

4. Faulty ABS Sensors   

Your ABS (Anti-Locking Brake System) helps keep you in control of your vehicle by preventing the wheels from locking up when you hit the brakes hard. One crucial part of that system is the network of ABS sensors that count wheel revolutions and help determine the speed you're traveling. When something is wrong with the sensors, your ECU isn't able to tell how fast your vehicle is moving. This may be down to an issue with the sensor itself or with the wiring. If something is wrong with those sensors or another part of the ABS, the speedometer may seem incorrect or simply fail to move at all.

Find an auto repair shop to learn more.