Updated at: 19-03-2022 - By: micdot

This article contains affiliate links. Using any of the links on this page will allow me to earn a small commission at no additional cost to you. You’ll notice a variety of telltale symptoms if something is amiss with your car. As a result, we must ask, “What are the signs of a faulty speed sensor?”

Perhaps your automobile isn’t working as well as it used to, and you’d like to find out if the wheel speed sensor is to blame? There are numerous indications that the speed sensor or sensors in your car are malfunctioning or broken. We’ve covered some of the most frequent ones in this post, but there are many more. In addition, the purpose of this article is to explain how speed sensors work and what problems they can cause.

What Are The Symptoms Of A Bad Speed Sensor?

You can think of speed sensors as simply reading the speed of your vehicle’s wheels and transmitting that data via “signals” to the ABS. The ABS uses these signals to alter your car’s engine performance.

This means that your engine’s performance will suffer, and you may also encounter additional problems if one or more of your vehicle’s speed sensors fails. The following are the symptoms of a faulty speed sensor.

Symptoms Of A Bad Speed Sensor

  1. Wrong Speedometer Reading

If your car’s speed sensor is malfunctioning, you may notice inconsistent readings on the speedometer because the sensor is responsible for transmitting information regarding the speed of your vehicle’s wheels. It’s difficult to drive safely if you don’t have a reliable speedometer reading.

  1. Driver Assistance Features/Techs Would Stop Working

Your vehicle’s driver assistance systems are immediately affected if your vehicle’s speed sensor is defective. This meant that features like cruise control would no longer be accessible. Your car’s other driver assistance functions would also stop working if you used them.

  1. Transmission Issues

If your car has an automatic transmission, faulty speed sensors might have a direct impact on the transmission. In addition to experiencing delayed shifts, harsh shifts, and the like, you’ll notice your car’s acceleration is decreased.

The transmission control module (TCM) uses speed sensor data to establish shift time, which leads to these problems. As a result, if incorrect or no information is passed, your automatic transmission engine will react in accordance with the signal it receives, resulting in delays, hard shifts, or other possible issues.

  1. Check Engine Light Would Appear

It is only when your car’s computerized systems detect an issue with your engine that the check engine light comes on. The check engine light can come on for a variety of reasons, one of which is a faulty speed sensor.

Use an OBDII scanner and perform a troubleshooting procedure to determine the specific cause of the check engine light on your dashboard.

  1. Hard Braking

Problems with the brakes are another sign of a malfunctioning or defective speed sensor. Your speed sensors may be defective and in need of replacement if your brake petals are difficult to match down.

What More?

These signs and symptoms aren’t specific to defective speed sensors; they could indicate problems with other parts of your vehicle as well. Therefore, the easiest way to determine if your speed sensors are defective is to conduct a thorough investigation.

Vehicle Speed Sensor Troubleshooting

You can use an OBD II scanner, a voltmeter, or even do the test manually as shown in the video above to diagnose speed sensors. It’s advised that you use an OBD II scanner to acquire the most accurate readings possible. How to manually test a vehicle’s speed sensors:

Make sure you have the engine off and your car in a secure spot before you proceed.

The location of a vehicle’s speed sensors varies from vehicle to vehicle; reference your vehicle’s owner’s handbook to find out where your vehicle’s speed sensors are located.

Disconnect the wiring harness connector from the VSS

Remove the sensor from its case. It’s important to note that each sensor is different, so be cautious when removing it and look for any screws that may be guiding it. Using a multimeter, plug in the sensor and set the meter to AC. A drill bit that will fit into the VSS is next. Attach the drill bit to the power source. The readings on the multimeter should be checked as soon as the drill is activated. The sensor is bad if the voltage doesn’t rise with speed, but it’s fine if the voltage increases.


What are the signs of a faulty speed sensor? Hopefully, this article solves this question. It’s best if you hire a mechanic if you find troubleshooting difficult or too technical. Also, we recommend that you get your car fixed as quickly as possible if there is a problem. Why? To avoid a more expensive repair, it’s better to take action as soon as you notice a problem.