Can a Failing Speed Sensor Cause Shifting Problems?

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Can a Failing Speed Sensor Cause Shifting Problems?

This article will provide information to answer the question “can a speed sensor cause shifting problems?”.

Can a Faulty Speed Sensor Cause Shifting Problems?

The answer is yes. To understand how and why the speed sensor causes shifting problems, we will first need to know more about vehicle speed sensors.

What Are Vehicle Speed Sensors?

Vehicle speed sensors (VSS) are commonly known as transmission speed sensors. It gives the onboard computer information about the speed of the vehicle. Its function is to calculate the actual transmission gear ratio while the car is in use. 

Two transmission speed sensors work in association with providing correct transmission data to a computer, commonly referred to as the powertrain control module (PCM).

The first speed sensor is known as the input shaft speed sensor to monitor the transmission’s input shaft’s speed shaft. The second sensor is the output shaft sensor.

Once data is registered, VSS transfers the data to transmission and engine control systems to gear transmission to drive efficiently. If the actual gear does not match the desired gear, the PCM will notify the driver to Check Engine Light through the Diagnostic Trouble Code.

In other words, when one of these two-speed sensors fails, it will impact the whole transmission operation and potentially impact the driver’s ability over the safety of the vehicle. 

Therefore, drivers would be highly recommended to notice some symptoms when one of the speed sensors is broken to replace when needed.

How Can a Speed Sensors Cause Shifting Problems?

One of the noticeable signs of a broken speed sensor is difficult shifting. When there is a faulty vehicle speed sensor, it can not send an accurate speed signal to the PCM. 

Therefore, the PCM will not control the gear shifting within the transmission and cause the transmission to shift roughly and not quickly as usual.

While an automatic transmission is controlled hydraulically, it is also designed to shift smoothly. Once the transmission is hard in shifting, it would damage hydraulic lines, valve bodies, and gear systems. Therefore, if the driver notices difficulty shifting, you should come to have your vehicle checked by a qualified mechanic as soon as possible.

What Else Could a Faulty Speed Sensor Cause?

Cruise Control Doesn’t Work

Apart from rough shifting, a failing speed sensor can cause broken cruise control. Depending on the vehicle type, other systems (for example, cruise control) also operate based on this data to keep your vehicle running at a stable speed.

When a speed sensor fails in delivering exact data to the onboard computer, the PCM will send an error code notification to the Engine Control Unit (ECU). As a safety warning, the ECU will close the cruise control and disable it.

Therefore, if you notice that the cruise control doesn’t work, let’s have your vehicle inspected by a mechanic to see why the cruise control is not working. There you know a bad transmission speed sensor may be one of the reasons behind this malfunction. 

Check Engine Light Comes on

Usually, VSS transfers the data to PCM, which compares these two inputs to determine gear transmission for the vehicle to drive efficiently. If the actual gear does not match the desired gear, the powertrain control module will notify you through the Diagnostic Trouble code to turn on the Check Engine Light on the vehicle’s dashboard.

Check Engine Light can also indicate an excessive increase in the tailpipe emission that exceeds the acceptable limits of environmental contaminants. The warning lights could also indicate a malfunction in the traction control system or anti-lock braking system (ABS) on the dashboard.

If you notice that the Check Engine Light comes on in any of the cases mentioned above, you should have your vehicle inspected to determine if the warning light is related to a faulty VSS. The tip is to connect your car to an OBD-II scan tool to see if the error code indicates a failing VSS.

Final Thoughts

To sum up, VSS are essential components that help transfer data to transmission and engine control systems to gear transmission to drive efficiently and safely.

Apart from causing shifting problems, a faulty vehicle speed sensor will cause the Check Engine Light to be on, and a malfunction of cruise control. While many reasons are causing such invisible symptoms, it might include the faulty transmission speed sensor.

While it is possible to drive your vehicle without a proper transmission speed sensor, it is not recommended. Having your car inspected at the right time by a qualified mechanic would ensure you know to replace the necessary component and prevent costly replacement of other problems down the line.

Knowing the symptom of a faulty speed sensor and having a timely replacement, thereby, would be an ideal way to ensure your ability to safe driving and maintain the vehicle’s life cycle.