Speedometer stopped working while driving.

Speedometer stopped working while driving

As a driver, whether you’re driving down the freeway or slithering in a traffic jam, your speedometer can stop working. Of course, you know that speed is one of the most important pieces of information you need to drive safely. This means that if your speedometer stopped working, you can’t be sure how fast you’re driving. The question is, have you ever wondered how your speedometer knows the exact speed?

The speedometer in the car is an instrument that provides the driver with instant readings of speed which is measured in Kilometer per hour (km/hr). Some speedometers use gears and wires to determine their speed, while most modern vehicles use speed sensors for the same.

Note that there are several common causes for a speedometer to stop working while driving. Normally, these malfunctions are caused by, a speed sensor problem, a broken gear in the speedometer system, or a faulty engine control unit (ECU).

Here are Symptoms of a Bad or Failing Speedometer

  • The Speedometer Needle Wavers

Your car speedometer is supposed to move fluidly as the vehicle accelerates or decelerates. But there are times when your car speedometer will waver or move erratically. And whenever this happens, it is usually due to the speedometer cable or speedometer sensors inside the transmission sending irregular data to the speedometer.

However, this symptom is usually noticed whenever you’re driving down the freeway, especially if the cruise control is set. Then you will see the speedometer move higher and lower, within 10 miles per hour if the speedometer cable is damaged.

  • A Squealing Noises Behind Dashboard

Please know that a squealing noise is never a good signal. Once you observe a squealing sound coming from behind the dashboard, this might signal an issue with the speedometer cable.

Sometimes this can be due to a speedometer cable that is going bad and sending sporadic data to the speedometer. So once you hear noise coming from the dashboard, contact your mechanic to locate where the problem is coming from.

  • The Speedometer Needle Does Not Move

Whenever the speedometer cable is broken, the needle on your speedometer will not move at all. Once you observe this, it’s important you contact a mechanic as soon as possible. This is because a malfunctioning speedometer is not only a potentially bad safety issue, but also a traffic infraction. So ensure to take this issue seriously to avoid any problem.

  • The Check Engine Light Comes On

Because your speedometer cable is electronic and sends data to the onboard computer, an issue with this unit will often trigger the Check Engine Light.  This is why you should always contact a professional mechanic to diagnose the issue before repairing any damaged mechanical part.

 

So What Causes The Speedometer To Stop Working?

As said before, the speedometers in modern vehicles use speed sensors to calculate their speed while the older models make use of gears and wires for the same purpose. Meaning the speedometer stops functioning whenever the sensors don’t work, dials malfunction, or the wiring becomes bad.

So just look into these components whenever your car speedometer stops working while driving.

  • A Malfunctioning Speed Sensor

Note that a speed sensor does not only indicate a vehicle’s speed, but helps with cruise control operation and also regulates the fuel flow and ignition timing. Your car’s speedometer may stop working while driving due to a bad sensor. And also, the affected cruise control can disrupt the driving functions of the car. This means that any problem with the sensor will make the Check Engine light to come on.

  • Problem With The ECU

Note that the Engine Control Unit (ECU) is literally the hub of engine activities, acting as the car’s computer brain. The ECU monitors and controls multiple engine activities, including speed. So it’s obvious that the speedometer may give wrong readings if the ECU has problems.

  • A Defective Wiring and/or Fuse

One other reason for the car speedometer not working is a bad wire. However, the wires can short out for many reasons, which causes the fuse to blow out and stops the operation of the speedometer. Though this mainly happens in older cars.

When my Speedometer Stopped Working while driving, I fixed it. So here is how do I fix yours.

Note that using a code scanner to examine the error codes is the first step to solving the problem. So to connect the scanner to the ECU to pinpoint the failed components. Also, know that it’s necessary to clear the error code to complete the repair process.

  1. Whenever The Sensors Have Failed

Look for the location of the sensors and examine them along with the wires connecting to them for any visible damage. Then replace the older one with the new unit in case if you have found any defect.

  1. Whenever The Wiring Is Bad

Sometimes the wires can short or worn out in an older car causing the fuse to blow out. So inspect both wiring and the fuse and then replace the faulty ones.

  1. In case The ECU Is The Culprit Here

Maybe the entire ECU needs replacement. Though you can reset it but it will only be a temporary fix. Please remember to rotate the ignition key to the auxiliary position once you finished the installation of the new unit.

However, don’t forget to test drive the car to ensure that the speedometer is working correctly. Because these are the repair processes that you should resort to whenever the car speedometer stopped working while driving.

 

Conclusion on speedometer stopped working while driving

Most times it’s rare that a problem with the speedometer cable will ever occur while driving, but it can happen. So whenever the issue does happen, it’s important that you have the speedometer cable replaced by your mechanic.

 

- Enovathemes