Why is my speedometer going up and down?
Simply so, why is my speedometer fluctuating?
If the hairspring comes loose or breaks, it can't hold the speed cup in place, and the result is a fluctuation in the dial. If a speed sensor in the automatic transmission starts to malfunction, it can affect the speedometer and cause fluctuations.
Secondly, what causes the speedometer and odometer 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. DID YOU KNOW: Sometimes you might have an issue where the speedometer is working, but odometer is not.
Correspondingly, what controls speedometer?
The ECU (engine control unit) converts the driveshaft's rotation speed to the vehicle's linear speed and then passes the information to the speedometer.
How do I know if my speed sensor is bad?
Most Common Symptoms of a Faulty Engine Speed Sensor
- Transmission revs higher before it changes gears.
- The car's transmission engages into overdrive late and sometimes will never go into that top gear.
- Brakes are sometimes harder than normal when coasting.
- Speedometer behaves erratically or sometimes does not work at all.