3 Reasons Your Speedometer Isn’t Working
The speedometer is an important part of the instrument cluster on your dashboard. Not only does it tell you how fast you’re driving, it’s often also linked to an odometer, which tells you how many miles or kilometers your car has traveled.
If your speedometer is broken, the first thing you need to do is check what type of speedometer your car has. Some models (even the same generation) use both types of speedometer implementations, and which one you need depends on the year of your vehicle.
How does a speedometer work? There are two types of speedometers: wired and electronic.
Cable Speedometer
A cable speedometer uses a cable that connects to the transmission. This cable runs from the transmission through the firewall to the cabin. This connects to the back of the instrument cluster and converts the gearbox rotations into a speed display on the dashboard.
Electronic Speedometer
An electronic speedometer uses a speed sensor instead of a cable. This sensor transmits speed data to the ECU, which converts this data into a ground speed display on the instrument panel.
Why does the speedometer not work?
1) Worn speedometer cable
If your speedometer needle skips or works intermittently, it could be that your speedometer cable is bad. When the cable wears out, it may stick or only work intermittently.
2) Faulty speed sensor
A defective speed sensor will affect the electronic speedometer. If the speed sensor fails, has a ground problem, or has bad wiring, the ECU won’t know how fast the transmission is turning and therefore won’t be able to tell you how fast you’re going.
3) Faulty Instrument Cluster
When an instrument cluster starts to fail, it’s common for the speedometer to stop working. If your instrument cluster is broken, you may also notice other gauges no longer working, such as: B. Coolant temperature gauge and fuel gauge.
If multiple gauges seem to be working at the same time, it’s more likely that the problem is with the instrument cluster, not the speedometer cable or speed sensor.
How to Fix a Broken Speedometer
The proper repair for a broken speedometer depends on the type of speedometer you have and the root cause of the problem. For Cable Speedometers
If you have a cable speedometer, the repair is often as simple as replacing a broken speedometer cable. This cable usually runs under the vehicle near the transmission, so it may be hard to reach on some vehicles.
For Electronic Speedometers (Check Engine Light)
If you have an electronic speedometer, the Check Engine Light will come on if the speed sensor fails. Perhaps your speedometer only works intermittently, or you’ve received a code for the speed sensor. Example: P0501.
Check the wiring to the speed sensor and the ground that sensor uses. If the wiring is OK, replacing the speed sensor will fix the problem.
Can I drive without a speedometer? You can easily drive without a speedometer, but for some reason you may not be allowed to do so. If your state or country requires a working speedometer in a road-legal vehicle, you could be fined for driving with a defective speedometer. The speedometer and odometer often work together. When the speedometer fails, the odometer may also stop working.
If the odometer stops working along with the speedometer, make sure you declare the mileage incorrect when you sell the vehicle. If you try to sell a car and intentionally under-state the mileage of the car, you could get into big trouble.
Does your cell phone work as a speedometer? Your phone’s GPS is fairly accurate, and in some cases even more accurate than your car’s speedometer. This is especially true if you’ve changed the tire size on your car and haven’t recalibrated the speedometer accordingly.
It’s possible to use certain apps on your smartphone in place of a speedometer, but this isn’t always legal. Check the laws in your area before using your phone instead. If you must use your phone, make sure you’re on speakerphone to avoid the risk of an accident.