Why is my speedometer fluctuating?

While you are driving, if you notice the needle on the speedometer jumps erratically from one number to another, the speedometer cable is most likely damaged or the sensors on the driveshaft are not accurately sending the signal through the cable. If this occurs, the entire cable and housing needs to be replaced.

Why does my speedometer keep going up and down?

You could have a problem with the speed sensor that provides information to the speedometer — either with the sensor, the driven gear, or the wiring or connector to the system. A good diagnostic tool should be able to monitor sensor output and test the system.

What would cause the speedometer to read wrong?

Reasons why your speedometer is inaccurate Damaged wiring or a blown fuse could be enough to through the speedometer out of whack. A malfunctioning sensor or engine control unit could be reporting an erroneous speed. A change in wheel or tire size could even throw off the senor and its calculations.

How do you fix a speedometer sensor?

Replacing Your Transmission Speed Sensors

1. Having found the sensor or sensors to be faulty, remove the connector between the sensor and the vehicle’s wiring.
2. Using the proper socket, remove the faulty sensor.
3. Connect the new sensor to the vehicle’s wiring.
4. Install the new sensor.
5. Lower your car.
6. Start the engine.

How do I know if my speedometer cable is bad?

Symptoms of a Bad or Failing Speedometer Cable

1. Speedometer needle wavers. The speedometer is supposed to move fluidly as the vehicle accelerates or decelerates.
2. Squealing noises behind dashboard. A squealing noise is never a good signal.
3. Speedometer needle does not move.
4. Check Engine Light comes on.

What will cause a speedometer to stop working?

The most common causes of a speedometer that stopped working include are a faulty speed sensor, a broken gear on the speedometer, damaged wiring, or a faulty engine control unit.