Vehicle Speed Sensor (VSS)

Описание: What Is A Speed Sensor?

A vehicle speed sensor (VSS) is a small component mounted on your car’s transmission that lets the car’s onboard computer know how fast you’re moving.

It’s also known as a wheel speed sensor, transmission speed sensor, or output shaft speed sensor.

How does the speed sensor work?

The vehicle speed sensor measures the rotational speed of the gears in your transmission system. Then, it converts this measurement into an analog signal or a low voltage square wave signal and relays it to electronic control units (ECUs) inside your car.

In turn, the ECUs use this signal to adjust your car’s speedometer readings, the ABS module, and transmission system.


Your car’s cruise control system may also rely on data generated by the speed sensor. Without it, your car wouldn’t be able to maintain a constant vehicle speed.
What Are The Symptoms Of A Faulty Speed Sensor?

Since your car’s speedometer readings, transmission systems, and cruise control depend on signals from the speed sensor, you need to ensure that it’s working as expected.

If you experience any of these symptoms while driving, you might need to get the vehicle speed sensor inspected and replaced:
1. Inconsistent Speedometer Readings

Most cars depend on signals from the wheel speed sensor to adjust their speedometer readings. A faulty sensor can result in inconsistent or erratic speedometer readings.

Alternatively, it can result in no readings at all.

This doesn’t mean that your car would simply stop working and you can’t drive it anymore.

However, with a malfunctioning speedometer, you’ll have no clue about how fast your car’s going, which can compromise your road safety.

If you notice that the speedometer is acting odd, consider getting your car inspected by a mechanic to check for any speed sensor failures.
2- Malfunctioning Cruise Control

In most cars, the cruise control system depends on input signals from the transmission speed sensor.

So if you’ve got a faulty speed sensor, you probably won’t be able to engage the car’s cruise control.

Why?

Generally, the powertrain control module (PCM) inside your car automatically disables cruise control when it fails to receive a proper signal from the VSS.

It does so because it’s impossible to maintain the constant vehicle speed needed for cruise control without transmission speed sensor data.

When you notice that the cruise control system in your car is malfunctioning, have a mechanic come over to check if you’ve got a speed sensor problem.


3-Harsh Transmission Shifting

Without a reliable signal coming in from the transmission speed sensor, the powertrain control module can’t correctly shift the gears within your transmission system.

What does that result in?

The PCM can cause rough gear shifts and impact the timing between your transmission shifts.

That’s not all.

If your car uses an automatic transmission system, a faulty sensor can also cause severe damage to the mechanical gear tooth profile and other internal components like hydraulic lines, valve bodies, and more.

To be safe, consider getting a car inspection soon to identify any transmission problems your vehicle might have.
for more information:
https://www.repairsmith.com/i/blog/sp...
https://www.standardbrand.com/en/prod...
https://www.obd-codes.com/p0500