How To Tell Which ABS Sensor Is Bad: Easy Ways You Must Know

How to tell which ABS sensor is bad is a very important thing for car owners to be aware of because the ABS system is an essential part of keeping you safe while driving. Driving can be risky if the ABS system isn’t working properly.

How To Tell Which Abs Sensor Is Bad

A defective ABS sensor is among the most typical issues with the ABS system. In this post, we’ll go through several techniques for determining which bad ABS sensor is malfunctioning.

How Can You Tell Which ABS Sensor Is Malfunctioning?

You can tell which ABS sensor is malfunctioning by inspecting it visually, scanning the ABS system, testing the resistance, using the dynamic testing method, or testing the brake pedal. Locating the bad ABS sensor is essential in order to fix it.

Take note that the Anti-lock Braking System (ABS), which uses all four wheel speed sensors to detect and avoid wheel lock-ups during braking, might be negatively impacted by a damaged ABS sensor.

In such circumstances, the ABS system may not function as intended, increasing stopping distances, decreasing steering traction control, and generally decreasing stability while braking. In order to guarantee the security and ideal operation of your vehicle’s braking system, it is essential to locate and repair any damaged ABS sensors.

– Inspecting Visually

This technique involves visually analyzing the ABS sensor for any indications of damage or deterioration. To check if the wires are properly connected and unharmed, you can follow them from the wheel speed sensor to their connecting location. You can also check the sensor housing for any physical harm, such as cracks or breaks, that might have resulted from normal wear and tear or impact from road debris.

Broken sensor housings may let moisture, filth, and other contaminants get inside the sensor, leading to dysfunction. It will probably need to be replaced if the ABS sensor has been harmed. Look for any obvious damage, such as fraying or cuts, on the wires. The wires must be well-fastened and clear of any corrosion or debris accumulation.

The wheel speed sensor can experience electrical resistance due to corrosion or debris, which interferes with its correct operation. Check for any accumulation of dirt, filth, or debris near the ABS light sensor. The sensor’s inability to detect the speed can be hampered by this buildup, which can have an impact on how well it performs. Clean the area completely and recheck the ABS sensor if you see any buildup.

The ABS sensor can be visually inspected to find any obvious evidence of deterioration or wear and tear that might be contributing to its malfunction. It is preferable to get the wheel speed sensor checked by a specialist to ensure its condition if you observe any damage or wear. A defective ABS sensor might interfere with traction control and stability control, activate ABS warning lights, and endanger your safety while driving.

– Scanning the ABS System

Scanning the ABS system with a diagnostic scan tool is another useful technique for identifying which ABS sensor is malfunctioning. The ABS system’s defects or error codes can be found using the tool for scan, which can also locate the problematic wheel speed sensor. This method can find hidden problems that might not be obvious to the unaided eye and is more accurate than visual assessment.

Scanning the Abs System with A Diagnostic Scan Tool

You’ll need a diagnostic scan tool that is compatible with the ABS system in your car to scan the ABS system. The diagnostic tool can be connected to the OBD-II port found on the majority of contemporary vehicles. Once connected, adhere to the tool’s instructions to access the ABS system and check for any error codes.

The tool for scan will display the code and its associated meaning if it finds a fault code associated with the ABS system or if the ABS light is on. The speed sensor that is failing and the nature of the issue will be disclosed by the code. For instance, the “C0040 – Right Front Wheel Speed Sensor Circuit” fault code denotes a problem with the right front ABS wheel speed sensor.

Via a diagnostic scan, you may locate the broken ABS sensor and prevent the needless replacement of functional sensors, which will save you both time and money. During a diagnostic scan, you can determine which ABS sensor is malfunctioning, and then you can follow the instructions to replace the sensor.

– Testing the Resistance

The resistance of an ABS wheel speed sensor can also be tested by using a multimeter to measure it. This technique works well for figuring out whether the sensor is functioning properly or not and can be used to spot a faulty ABS sensor. Locate the wheel speed sensor on your car in order to check its resistance. The ABS sensor is often attached to the wiring harness by a connector and is situated close to the wheel hub or axle.

Set your multimeter to the ohm setting and then disconnect the wiring harness from the sensor. Next, connect the terminals on the sensor with the multimeter leads. For the majority of automobiles, the multimeter should display a resistance measurement of between 900 and 1300 ohms. The sensor has to be changed if the reading falls outside of this range and is indicative of sensor failure.

You can also check the signal output of the sensor to see if the resistance is within the typical range. To do this, manually turn the wheel while checking the multimeter reading. As the wheel rotates, the reading should change, demonstrating that the sensor is picking up changes in the speed. The sensor is most likely defective and has to be changed if the multimeter reading does not change while the wheel spins.

Finding out if the sensor is defective and has to be replaced is a reasonably easy and affordable process. It’s crucial to remember that not all malfunctioning sensors will produce anomalous resistance readings, and a diagnostic scan may be required to pinpoint the exact site of the issue.

– Dynamic Testing Method

This technique test ABS sensor while the car is moving and can assist in finding sensor problems that would not be seen during static testing. You must attach a tool for scanning to the car and start a live data feed in order to run a dynamic test. You will be able to view the speed data from each wheel speed sensor in real-time while the car is moving thanks to this.

Test Abs Sensor While the Car Is Moving

Drive the car at a slow, secure speed after starting the live data stream, and keep an eye on the speed readings. Very slight changes resulting from variations in tire wear or other variables should be present across all four wheels.

If one or more of the speed measurements differ noticeably from the others, it might be a hint that the relevant ABS sensor isn’t working properly. For instance, if the reading from the front left wheel sensor is much lower than the readings from the other three, it can be a hint that the sensor is malfunctioning.

– Testing the Brake Pedal

A malfunctioning ABS sensor can also be found using the brake pedal. While using the brakes, this technique entails looking for odd or irregular braking behavior. Drive the car at a safe, slow speed while conducting this test, then brake hard. Pay close attention to how the pedal of brake feels as you apply the brakes.

Malfunctioning Abs Sensor Can Be Found in The Brake Pedal

The anti-lock brakes system or one or more of the wheel speed sensors may be malfunctioning if the pedal of the brake feels spongy or soft. Moreover, pay attention to how well the car brakes. When the brakes are engaged, the car may pull to one side or the other. This could be a sign that the ABS system or sensors are malfunctioning.

Unreliable ABS wheel speed sensors that provide the ABS module with false speed data might result in uneven braking. A decrease in braking pressure is another potential problem that can be discovered through the pedal of the brake. The module of ABS may release brake pressure inadvertently as a result of a defective wheel speed sensor, which could reduce braking effectiveness. The presence of a spongy or sluggish pedal of the brake can indicate this.

Can a Bad ABS Sensor Affect the Functioning of a Floor Jack?

Using a floor jack correctly is essential for safe operation. However, a bad ABS sensor should not affect the functioning of a floor jack. The ABS sensor is responsible for monitoring the wheel speed and is unrelated to the mechanical function of a floor jack.


All in all, knowing how to tell which ABS sensor is bad is important for maintaining the performance and safety of your car.

You can easily identify a bad ABS sensor by using the techniques in this article, and this is a quick summary of everything:

  • Visually check the ABS sensor for deterioration or damage.
  • To find trouble codes, scan the ABS system with a diagnostic tool.
  • To find out if the ABS sensors meet the manufacturer’s requirements, test their resistance.
  • Check for inconsistent speed readings by conducting a dynamic test while driving the vehicle.
  • Check for irregular or spongy braking performance by pressing the pedal of the brake.

Faulty ABS sensor replacement as soon as possible can help prevent further damage to the ABS system and ensure the safety of you and your passengers. However, you have to take note of the replacement cost.

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