5 Bad Abs Sensor Symptoms: How To Tell Which Abs Sensor Is Bad

Significantly, your vehicle’s abs sensors send countless vital information to the ECU for the proper functioning of other components in your automobile. In conjunction with the system’s functioning, Abs sensors are responsible for picking up data from each wheel in your vehicle before sending them to the ECU.

So far, a bad or faulty Abs sensor (s) can make your ABS perform inaccurately or even stop functioning and affect the entire system. In order words, you can notice bad sensor (s) with some significant symptoms like Abs warning light, lack of stability, and skidding, but to mention a few. 

In essence, this article will bring into lamplight and enable you to understand the following contents properly; how to tell which ABs sensor is bad, bad ABs sensor symptoms, what happens when a wheel speed sensor goes bad, how to test an ABs sensor, how to test an ABs sensor with a multimeter, can a bad ABs sensor cause vibration, what causes wheel speed sensor failure, bad wheel speed sensor noise, and more to come your way.

Relax, let’s get into the full detail!

bad ABs sensor symptoms

How To Tell Which Abs Sensor Is Bad

It is indispensable that a mere disassembly of your wheel hub to have a clear sight of the Abs sensor wouldn’t certify or prove it excellent or lousy.

Nevertheless, if the Abs sensor is not damaged physically, you would need a technical troubleshooting device like a scan tool to run the diagnostic test to certify the actual fault or the faulty one. Though using the OBD2 scanner will enable you to get a quick result.

Here you have the easy steps to carry out the test!

  • Fix the scan tool to your vehicle.
  • Follow the manufacturer’s guide as you boot the scanner to detect your vehicle’s VIN.
  • Click on the “Control Unit” once the scan tool has detected your car’s VIN.
  • Click on ABS to load the vehicle’s data as regards the anti-lock brake system.
  • Click on “Read Codes” and wait for a few seconds.
  • Error codes will display on the scan tool, indicating which Abs sensor is bad or lousy.
  • To get a precise result, return to the previous interface where you clicked the “Read Codes” and click on the “Live Data” as it will display information regarding all components of the braking system (ABS).
  • Scroll down to check for Wheel Speed Sensors or ABS sensors.
  • As your vehicle is still, each Abs sensor should read “Zero.” If any of the sensors read above or below zero, it is not very accurate since your car is not in motion.

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Let’s start with the symptoms of a bad Abs sensor without much ado.

1.    Improper Transmission Shift

A bad Abs sensor will contribute highly to the transmission shifting gears improperly or even with a jerking sign. Though a lousy sensor sends inaccurate data (wheel speed values) to the transmission, the transmission cannot decide on the appropriate gear for your vehicle, causing your engine to stall or even lock up in the first gear. So, if you should replace bad Abs sensors, the jerking and stalling will cease, but if not replaced, catastrophic issues could arise on your vehicle’s transmission. 

2.    Steady Abs Light 

Although the Abs light functions in line with the check engine light. So, if the Abs light comes on, this warning light indicates something is amiss with your ABS. The steady warning light as you drive could signal a bad Abs sensor.

3.    Traction And Disable Stability Control

Realistically, your vehicle’s antilock brakes aren’t the only vital parts that depend on the proper operation of the ABS. For sure, the stability and traction control systems use the data from the Abs sensors to enhance stability control and assist in hill-start and various other functions. So far, a bad sensor will disable the functionality of the systems if not replaced.

4.    Erratically Working Of The Abs

An erratic ABS (a system that works sometimes and sometimes may not) could compromise your vehicle’s safety efficiency since you never had any guarantee that it could be functional when you needed it most. Though it doesn’t pay to gamble with faulty or lousy vehicle components, do replace them at the necessary time!

5.    Instability While Braking

Traditionally, the ABS works effectively upon heavy braking to quickly slow your vehicle without locking up the brakes as it sends your vehicle into skidding. In essence, the data collected by the Abs sensor modulate the braking pressure to prevent lock-up and loss of traction during hard stops. Hence, a bad Abs sensor can lock up the brakes as it deactivates the ABS.

If you have spotted any or some of the symptoms mentioned above of a bad Abs sensor, it will be wise of you to diagnose and install a new one sooner than later.

What Happens When A Wheel Speed Sensor Goes Bad? 

Possibly, if your vehicle’s wheel speed sensor goes wrong, it will turn off its traction, stability, and other safety assist systems. Nevertheless, damaged wiring could also prevent the Abs (wheel speed) sensor from feeding data to the control module.

Although other vital issues that could arise from the failure of the wheel speed sensor include;

  • Pulsating brake pedal
  • Abs warning light comes on
  • Disable speedometer
  • Skidding of your vehicle
  • Brake lock-up

How To Test Abs Sensor

Some simple, easy procedures are vital for achieving your goals of testing the Abs sensor.

Here you have these procedures;

  • Firstly, get a voltmeter and locate the position of the Abs sensor in your hub.
  • Disconnect the Abs wires carefully and clamp the voltmeter probes to the Abs sensor correctly.
  • When the connection is complete, please turn on the voltmeter as you set it to an alternating current (AC).
  • The voltmeter reading should drop to zero to enhance accurate testing and reading.
  • If the Abs sensor is functional, the AC voltage reading should be about 400. Although, your task could depend on how fast or slow you spin the hub and can vary in each vehicle.

When carrying out the above procedures correctly, and you have the correct reading, you can move to the other Abs sensors, but if the reading is off standard, check behind the wheel for a gear-teeth called Abs reluctor. I recommend you get a certified mechanic to do the above test, or you could if you have much experience to avoid damaging the wheel speed sensor since they are magnetic.

How To Test An Abs Sensor With A Multimeter? 

To test the Abs sensor with a digital multimeter requires some tools to complement the achievement of this test proposal.

Prerequisite Tools

  • Car jack
  • A floor creeper
  • An engine code reader
  • Brake set tools, test light
  • Battery charger, ramps, and other necessary tools.

Let’s get the job done!


  • Set up the multimeter as you have disconnected the sensor.
  • Select your range as you place the needle in the middle scale.
  • Avoid the high or low scale range as you select the medium value because a low value will show that the multimeter will peg for most results, while a high value indicates that the needle would not move for the correct reading.
  • Zero out the multimeter as you connect the red and black wires to the pins of your vehicle’s Abs sensor.
  • Check the resistance display.
  • The Abs sensor is bad if you have a deviation of 10% from your manufacturer’s manual.
  • Install a new one to function your anti-lock brake system effectively.

Simple right?

Can A Bad Abs Sensor Cause Vibration? 

Possibly, yes! A bad sensor can cause vibration in your vehicle as it could enhance the braking system to have a soft brake pedal. In addition to the Abs sensor’s erratic behavior, your brake might lock up and, in the process of that, can vibrate before it stalls.

What Causes Wheel Speed Sensor Failure?

The efficacy of the wheel speed sensor can’t be over-emphasized as it can be affected by some factors.

Here you have them!

  • An internal electrical faulty in the wheel speed sensor.
  • Exposing your wheel speed sensor to some environmental elements.
  • Lack of timely vehicle maintenance.

Bad Wheel Speed Sensor Noise

It is noteworthy to put it forward that despite various areas, a bad wheel speed sensor affects as it shows its symptoms which I have highlighted above. Nevertheless, a bad wheel speed sensor can cause a noise (a clicking sound) from your car’s wheel. It is wiser to solve an issue at its initial stage than when it has become complex.


You must now know the symptoms of a bad Abs sensor and how to find out which sensor is wrong using a voltmeter, as you connect the Abs sensor to the voltmeter and gently turn the wheel to get a more accurate reading.

Although, a multimeter and scan tool are also functional for checking and detecting a lousy Abs sensor. Similarly, checking the Abs sensors is not tricky, and finding which is faulty to replace them isn’t complex too.

You would need to lift your car with a jack to get the wheels off, locate the sensor in the hub, and diagnose and install a new one if there is any lousy one to keep your ABS functional in no time. Remember driving with a faulty ABS can be dangerous; of course, I recommend you consult a certified mechanic or technician for the effectiveness and efficient working of your vehicle. Do like and share this informative article with others!

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