There are two types of speed sensors available for a vehicle. There is the engine speed sensor and the transmission speed sensor.
The engine speed sensor detects the number of revolutions per minute (RPM) of your engine’s crankshaft in real time. The transmission speed sensor detects the speed at which your car is traveling on the road.
When you look at your dashboard, you can see the tachometer representing the engine speed and the speedometer representing the transmission speed. Both sensors continuously communicate with the vehicle’s engine control unit.
The information that the engine control unit receives from these sensors will allow it to take appropriate actions with the operation of the engine and transmission. All sensors are equally important and have an indirect impact on the other components of the vehicle.
Symptoms of a Faulty Speed Sensor
Transmission speed sensors are integrated into your vehicle’s wheel hubs. This is how the vehicle’s speed and movement are calculated by these sensors. However, your vehicle’s transmission depends on both types of speed sensors to function properly.
If one or both of the sensors were not working correctly, you would experience a wide variety of symptoms from your vehicle. These are not symptoms that you could tolerate for very long, as they will severely affect your ability to drive safely.
Below are the 4 main symptoms of a faulty speed sensor that you should watch out for.
1) Faulty Cruise Control
Transmission speed sensors must be functional for your cruise control mechanism to work properly. If the engine control unit cannot receive proper information about the vehicle’s speed, your cruise control will never be able to maintain the same speed.
The engine control unit will be able to detect this problem, so it automatically prevents the use of cruise control until the issue is resolved. If you don’t normally use cruise control but suspect your speed sensors are faulty, test them by trying to use the cruise control and see what happens.
2) Check Engine Light
When the “Check Engine” light comes on, it can mean almost anything. But if you have a faulty cruise control and a Check Engine light that comes on, it’s a clear indication of a faulty speed sensor.
After all, the engine control unit needs valid speed information regarding the engine’s crankshaft. If it doesn’t receive this accurate information, it will alert the driver by automatically turning on the “Check Engine” light.
3) Long Shift Intervals
The engine control unit communicates with the transmission. If the transmission speed sensors end up failing, the unit will not be able to properly manage the shifting actions you perform.
As a result, you may notice that the timing of your gear shifts will be off. This means there will be a small waiting period between each shift you make.
4) Difficulty Shifting
In addition to the shifting intervals you’ll experience, shifting gears will be more difficult in general. You may notice that the stick shift feels more abrupt when you try to change gears or that it feels too fast.
In order to be a safe driver, the shifting experience should be smooth. It should be neither too difficult nor too easy.