The speed sensor in your car performs a variety of tasks, from telling you how fast you are going, to directing a vehicle with automatic transmission when to change gears. When this sensor malfunctions, the result can be a vehicle that is acting strangely. If you are trying to figure out whether the speed sensor in your car is working or not, here are 5 common symptoms of a failing speed sensor.
- Cruise Control Doesn’t Work
Since the speed sensor is responsible for establishing how fast the car is going, cruise control won’t work properly if it is faulty. Fortunately, this doesn’t mean an out of control car going too fast, or a car that slows down to a stop. Instead, when the vehicle senses the speed sensor is malfunctioning, it sends an error code that disables cruise control completely. Even if you haven’t read the codes, if you notice cruise control no longer works it is a big clue that your speed sensor is either failing or completely nonfunctional.
- Your Check Engine Light Is On
When the vehicle detects any error inside the engine, the check engine light is triggered. Since the check engine light can be from any error detected by the engine, this does not necessarily mean it is the speed sensor. If the check engine light comes on, pulling the codes can help you confirm whether it is the speed sensor or not.
- Timing Of The Shift Is Slower
Another common symptom of a failed or failing speed senser is that shifting gears in an automatic will be difficult. The transmission relies on input from the speed sensor in order to decide when to shift, and if it isn’t working properly the speed sensor may have difficulty choosing when to shift.
You may also notice the engine running rougher as the vehicle struggles to shift, or sound off when idling. This is another common symptom that could help you confirm that the speed sensor is your issue.
- Your Speedometer Is Not Working
A slightly more obvious symptom is when the speedometer isn’t working properly. This doesn’t have to mean that your speedometer has quit working completely, it could simply fail to work properly, and then other times behave as if nothing was ever wrong.
This may make you feel like you’re going crazy, but it could also be your speed senser acting up.
If you notice all or some of these symptoms, a bad speed sensor could be the problem. To confirm the problem, it’s best to get a computer diagnostic on your car. The diagnostic can check for transmission problems, which can behave in a similar way to a speed sensor issue.
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If it is a speed sensor, replacing it may be difficult depending on the location of the failed sensor. Some speed sensors are inside of the transmission itself, and require the transmission to be completely removed in order to replace it.