How Do I Know If My Wheel Speed Sensor Is Bad on My Jeep?

Modern cars come with driver-assist features like the electronic stability system, the traction control, the anti-lock braking system(ABS), and many other cool features.

The wheel speed sensor is integral to the functioning of some features, especially the anti-lock braking system.

Therefore, it is apparent that when your wheel speed sensor is faulty, your smooth driving stalls. Today, I’ll tell you how to recognize the early signs of a bad wheel speed sensor.

A faulty abs sensor manifests in several ways. However, some symptoms are common and easy to identify. For example, when your jeep’s wheel speed sensor is bad, the indicator light for the anti-lock brake system on the dashboard turns on. Also, the anti-lock brakes stop working correctly, and the brake pedal fluctuates. 

How Do I Know If I Have a Bad Wheel Speed Sensor?

Knowing whether or not you have a bad-wheel speed sensor is easy. You need to look out for these five signs that give you subtle hints. 

#1. Warning Lights for the Anti-lock Brake System Turning On

To provide you with a safe brake control when you’re driving in harsh situations, many cars nowadays come fitted with an electronic stability system, traction control, and an anti-lock braking system.

They work in harmony to provide you with a smooth driving experience. 

The ABS wheel speed sensor feeds all these systems information about your car wheels.

As you may have noticed, your dashboard has the traction control light indicator, the ABS light indicator, and the Check Engine Light indicator.

Unfortunately, a bad speed sensor trips all these indicators on. 

#2. Your Anti-lock Brakes Won’t Function

Under normal conditions, your car’s anti-lock brake system receives signals from the wheel speed sensor about the state of the wheel.

From this data, the anti-brake system then establishes whether or not the wheels are restricted from hard braking.

A faulty wheel speed sensor doesn’t perform this function, so the anti-lock brake system does not get the signals.

The anti-lock brake system controller puts off the anti-lock brake when this happens. That is why it doesn’t work. 

#3. Fluctuating Brake Pedals

All the wheels of your car have their own ABS wheel speed sensor. Each sensor monitors the speed of the wheel to which it is connected.

When you have a bad wheel speed sensor, the data it sends to the anti-lock brake system controller is incorrect.

The controller then assumes that your car is sliding off the road and automatically triggers the anti-lock brakes.

As a result, anti-lock brakes rapidly pump the brakes by releasing the brake pressure. Therefore, your brake pedal will fluctuate when you tap it. 

#4. Stability and Traction Control not Functioning

Your car comes with some driver-assist features like stability control, traction control, and other features.

Unfortunately, when your wheel speed sensor is bad, it switches off these driver-assist features.

Consequently, you won’t be able to effectively maintain good traction with the road in harsh weather conditions like rain, snow, etc. 

Additionally, your brakes will develop problems regularly. Whenever you pick up any of these problems, you should not neglect them as this decision can be costly in the long run.

Instead, you should schedule a visit to your dealership or your local mechanic and get your bad-wheel speed sensor diagnosed and replaced.

#5. Faulty Speedometer Reading

When your speedometer stops working, it could also be a telltale sign that you have a bad wheel speed sensor. Although rare and less common with newer cars, it can also be a good pointer.

You should always swiftly fix a bad speedometer. That is a safety hazard for other drivers and you since you don’t know whether you drive too fast or slowly.

How Do You Test a Jeep Wheel Speed Sensor?

You can test the wheel speed sensor for your jeep with a multimeter.

The wheel speed sensor and the anti-lock braking system work in tandem to ensure you drive your vehicle smoothly. Almost all modern cars come with both facilities. 

The wheel speed sensor picks up the wheel’s rotational speed, interprets this information, and sends it anti-lock brakes.

For instance, the wheel speed sensor notices that a wheel is locked-up or isn’t rotating. It transfers this data to the anti-lock braking system.

When the anti-lock braking system receives the signal, it automatically reduces the brake pressure so that the wheel can resume rotation.

When the sensor is bad, this function becomes impaired. Hence, it’s important to test your wheel speed sensor to see if it’s working properly.

Here’s a detailed guide on how to test your ABS wheel speed sensor:

#1. Step 1

Here, you need to get all the materials you’ll need ready so that you don’t look for a tool while testing. The equipment you need includes:

• Jack stands
• Floor jack
• Voltmeter or multimeter
• Torque wrench
• Tire iron
• Flying leads
• An assistant

After getting the tools ready, the next thing to do is park your jeep on a flat surface, place the transmission in neutral or park mode, put the emergency brakes on, and turn your jeep off.

#2. Step 2

Next, you need to find the anti-lock brake system fuse in the main fuse block of your vehicle. If you need help, consult your owner’s manual for the precise location.

However, the likely location of the main fuse block is the engine compartment, the glove box, or the sidekick panel of the driver.

Once you find the main fuse block, remove the lid and look for the anti-lock brake system fuse. 

Check the filament in the anti-lock brake system fuse and ensure it is in one piece. If it’s broken, replace the entire fuse with a new one. 

#3. Step 3

Using the floor jack, lift the front and the rear part of your jeep with a floor jack and rest the frame on two jack stands close to the wheels.

Afterward, using a tire iron, loosen all lug nuts on the wheels and remove the wheels.

#4. Step 4

The next step is to turn off the emergency brakes and put the transmission in neutral. Then isolate the connector wire underneath the brake disc close to the wheel frame and inspect it closely.

#5. Step 5

The next thing to do is place the multimeter in the Alternating Current(AC) or Voltage setting.

After that, attach the multimeter’s probes (aka voltmeter) to the connector terminals (which are from the wheel speed sensor) and note the voltage reading. This reading should be zero. 

#6. Step 6

Then ask your assistant to spin the wheel hub manually as fast as possible. Please don’t allow the probe to touch each other during the test, as it’ll give you a bad reading.

The voltage reading should give you about 400 volts, depending on how fast your assistant spins the wheel.

If there is no change in the voltage reading, your jeep’s wheel speed sensor is bad and needs replacement.

How to Tell Which Wheel Speed Sensor Is Bad?

To know which wheel speed sensor is bad, you have to carry out the multimeter or voltmeter test described above. It can be a lengthy process, and you should be well prepared.

You conduct the test on all four wheels with the aid of an assistant, a multimeter, and the other materials I mentioned above. Read more to know whether My Jeep Shocks Are Bad or not?

Once you attach the connector wire of the first wheel sensor to the multimeter probes, you should get a reading on the multimeter.

The wheel that does not give a voltage reading on the multimeter is bad, and you should replace it. Then repeat all the steps on the remaining three wheels because each wheel has its sensor.

Symptoms of a Bad Wheel Speed Sensor?

I have thoroughly discussed the symptoms of a bad wheel speed sensor above. However, here’s a quick list of the five common symptoms of a faulty wheel speed sensor.

• Your anti-lock braking system indicator light on the dashboard is on
• Your car’s traction control indicator light is also on
• You may have trouble with your automatic transmission system. Examples include hard shifting, delayed shifting, and restrictions in the gear functions
• Speedometer problems
• You may have difficulties using your engine cruise control

What Happens When a Wheel Speed Sensor Goes Bad?

When your wheel speed sensor goes bad, your anti-lock brake system does not function properly.

That is because the vehicle speed sensor works together with the anti-lock brake system to ensure smooth driving of your car. 

A vehicle speed sensor connects to the wheels through a delicate network, and it reads or senses the speed of rotation of the wheels.

It then sends this information to the anti-lock brake system, which then decides if it’ll reduce the pressure on the brakes or not depending on road conditions like snow, rain, etc. 

The wheel speed sensor also helps in the seamless functioning of other driver-assist features like the electronic stability system, traction control, engine cruise control, etc.

These driver-assist features malfunction when your wheel speed sensor is bad. 

Even though it is possible to drive your car with a bad wheel sensor, it is not safe for you, your passengers, and other road users.

Therefore, I strongly recommend that you take your bad speed sensor for replacement when you notice any of these symptoms mentioned above.

What Causes Wheel Speed Sensor Failure?

A wheel speed sensor can fail for a lot of reasons. Nevertheless, the most common causes include:

• The speed sensor develops a fault in its internal electrical system
• There is a crack, break, or damage to the speed sensor
• Damage to the magnetic part of the sensor
• Failure to adhere to the routine maintenance schedule

Final Thoughts

Everyone will like to enjoy the comfort of a smooth drive. Unfortunately, a bad-wheel speed sensor gives you the complete opposite.

That is because a bad wheel speed sensor interferes with the normal functioning of the anti-lock brake system and other driver-assist features.

Therefore, whenever you notice a faulty wheel speed sensor, you should report it to your automobile mechanic.