How to Test ABS Sensor

The Anti-lock Braking System (ABS) plays a crucial role in vehicle safety by preventing wheel lock-up during braking, especially in emergency situations. Within the ABS system, the ABS sensor plays a vital role in providing real-time data about wheel speed to the vehicle’s computer.

How to Test ABS Sensor

However, over time, the ABS sensor can become damaged or malfunction, compromising the system’s effectiveness. That’s why knowing how to test an ABS sensor is essential for maintaining optimal braking performance. In this article, we will explore the step-by-step process of how to test ABS sensor.

By following these guidelines, you can diagnose potential sensor issues, identify faulty components, and take appropriate measures to ensure the ABS system functions correctly. Whether you are a DIY enthusiast or simply want to understand the workings of your vehicle’s safety features, this guide will equip you with the knowledge to perform an accurate ABS sensor test.

How Can You Tell if an Abs Sensor Is Bad?

There are several signs that may indicate when an ABS sensor has gone bad. Your first indication might be a warning light on your dashboard indicating that the system is malfunctioning. Additionally, you might experience steering control problems, longer stopping distances, and/or pulsating brakes or brake pedal vibration during braking.

If any of these symptoms occur, you should have the system checked immediately. To test an ABS sensor, mechanics usually use a specialized scanner to read out any codes and troubleshoot the issue. If there is a problem with the sensor, it will need to be replaced.

Test an Abs Sensor

If you are able to determine that your ABS Sensor has gone bad, it’s important that you replace it as soon as possible. An ABS sensor is an important piece of safety equipment, and not replacing it could to serious consequences in the event of a sudden impact on another vehicle.

To ensure that the new sensor functions correctly make sure you check for any damage to the wiring, connectors, and other parts of the system. Additionally, you may need to perform a ‘drive cycle’ after replacing the sensor in order for the ABS light to turn off.

What Is the Voltage of the ABS Sensor?

The voltage of the ABS sensor depends on the make and model of your vehicle. Generally, sensors will typically output a range between 0 and 5 volts when they are operating properly. To check the voltage of the ABS sensor accurately, you should connect a voltmeter to its terminals. Make sure that you consult your vehicle’s manual to determine which terminals should be used if you are unsure.

Once the voltmeter is attached, start the car and then press on the brake pedal. The voltage reading at this time should indicate whether or not your ABS sensor is working properly. If the voltage does not increase or decrease significantly when the brakes are pressed, it could be an indication that the sensor is faulty and may need to be replaced.

Press on the Brake Pedal

If you are unsure, it is best to consult a professional mechanic before attempting to replace or repair the ABS sensor yourself.

In addition to checking your ABS sensor’s voltage, you should also inspect its wiring harness for any signs of damage. Make sure that all connections and plugs are secure and free of corrosion, as this can cause electrical shorts and malfunctions. If you find any damage to the wiring harness, it is best to consult a professional mechanic for repair.

10 Methods How to Test ABS Sensor

1. Visual Inspection

Start by visually inspecting the ABS sensor and its wiring for any signs of damage or corrosion. Look for frayed wires, loose connections, or physical damage to the sensor. If any issues are found, they may require repair or replacement.

When everything looks good, move on to the next step. Make sure to clean the sensor and its wiring beforehand if necessary. However, be sure not to use any solvents or harsh cleaners, as these may damage the sensor. Try to use only a dry cloth.

2. ABS Error Code Scan

Use a diagnostic scan tool to retrieve any error codes related to the ABS system. The error codes can provide valuable information about which sensor or component may be experiencing a problem. Refer to the vehicle’s service manual or online resources to interpret the error codes. A qualified mechanic should be consulted to ensure the correct diagnosis and repair.

While the ABS system can be tested manually, it is best to leave this job to an experienced technician. Though it is possible to replace the defective component yourself, doing so without a professional’s guidance could lead to further damage.

3. Wheel Speed Sensor Test

Connect a multimeter to the wheel speed sensor’s electrical connector and set the multimeter to the AC voltage mode. Rotate the wheel by hand and observe the multimeter reading. A functioning sensor should produce an alternating current (AC) voltage signal as the wheel spins.

Connect a Multimeter to the Wheel Speed

Compare the readings across all wheels to ensure consistency. If the wheel speed sensor is malfunctioning, it may produce an incorrect AC voltage signal or no signal at all. In this case, replace the wheel speed sensor and then retest.

4. Sensor Resistance Test

Disconnect the ABS sensor’s electrical connector and measure the resistance across its terminals using a multimeter. Compare the reading to the manufacturer’s specifications. A significant deviation from the specified range may indicate a faulty sensor that needs to be replaced. Testing the ABS sensor’s resistance is an effective means of confirming its functionality.

If the resistance value is within the specified range, it is likely that the sensor is working correctly. However, improper connections or other external factors may still affect its output. Therefore, further testing may be necessary to verify the sensor’s health. For example, the resistance test should be repeated after making sure the sensor is securely connected.

5. Sensor Signal Test

Connect an oscilloscope to the ABS sensor’s electrical connector and set it to the voltage waveform mode. Spin the wheel and observe the waveform displayed on the oscilloscope. The signal should exhibit a regular pattern of voltage spikes.

Any irregularities or inconsistencies in the waveform may indicate a faulty sensor. As an additional test, the resistance of the sensor can also be measured with a multimeter. The expected resistance value should correspond to what is specified for the particular sensor. If the resistance is significantly out of range, it may indicate a failing sensor.

6. Magnetic Ring Inspection

Inspect the magnetic ring or tone ring near the wheel speed sensor for any damage or missing teeth. A damaged or distorted ring can disrupt the sensor’s ability to detect wheel speed accurately.

If necessary, replace the ring and retest the sensor. Be aware that ABS sensors are sensitive and must be handled carefully when performing the inspection. When reinstalling the sensor, ensure it is properly oriented and secured in place.

7. Wheel Bearing Play Test

Excessive play in the wheel bearing can affect the accuracy of the ABS sensor readings. Safely lift the vehicle and wiggle the wheel in different directions to check for any noticeable play. Excessive play may require bearing replacement or adjustment.

Also, be sure to check the condition of the wheel bearing seals for any signs of leaking or damage. If there are signs of wear, take the necessary steps to repair or replace the bearings as instructed by the vehicle’s service manual.

8. Sensor Wire Continuity Test

Use a multimeter set to the continuity mode to check for any breaks in the sensor’s wiring. Connect one multimeter lead to the sensor’s electrical connector and the other lead to the corresponding wire’s other end.

A continuous tone or a low resistance reading indicates proper wiring continuity. If a resistance reading is higher than anticipated, then the wire may be damaged and require replacement. Disconnect all connections before starting this test.

9. Road Test and ABS Activation

Take the vehicle for a road test, preferably in a safe and controlled environment where you can activate the ABS system. Apply the brakes firmly and observe if the ABS system engages properly. Pay attention to any unusual noises, vibrations, or inconsistent braking behavior, which could indicate a faulty sensor.

Vehicle for a Road Test

10. Professional Assistance

If you encounter persistent issues or are unsure about performing the tests yourself, it is advisable to seek assistance from a qualified mechanic or automotive technician. They have the necessary expertise and specialized tools to diagnose ABS sensor problems accurately.


To conclude, it is important to know how to test an ABS sensor and to be aware of the issues that may arise if your system does not operate properly. By following these steps, you can take the necessary steps to ensure the safety of yourself, your passengers, and other drivers on the road. Properly testing your ABS sensors regularly helps keep your car safe and ensures its long-term operation.

Always refer to your vehicle’s manual when you are set out to perform any maintenance on your vehicle and consider consulting a certified mechanic for any complex tasks. If this information was beneficial or helpful in any way, don’t forget to bookmark us so that you can easily come back in case you need more help with How to Test ABS Sensor

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Enrique Howard

Hi, I am Enrique. I started my professional life as a handyman and did a lot of external and internal repair of home and office with a little bit of electric and plumbing support. I have extensive experience in tools testing such as drilling, turning, milling, and non-conventional machining like EDM. So let me help you on your journey towards becoming an enlightened DIYer with amazing tools that you can use on your project.

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