How To Test ABS Module With Multimeter

The ABS light on your dashboard suddenly begins to shine as you’re enjoying the drive. Also, you begin to notice a stiffening of your anti-lock brake and a lack of reaction from your brake pedal. It seems like there is a problem…and that ABS light has a role in it.

Every car wheel rotates at a different speed, which the ABS sensor records. The ECM evaluates each wheel’s locking-up state after receiving wheel speed reports. ECM locking-up mechanisms are the cause of a sudden grinding sound coming from the brakes.

This article will cover everything you need to know about How To Test an ABS Module With a Multimeter.

Understanding the Anti-Lock Braking System (ABS)

To understand the ABS control module, we first need to know what an ABS is.

During heavy braking, the Anti Lock Braking System (ABS) is designed to prevent your wheels from locking, skidding, or hydroplaning. Since the 1980s, it has been a further safety element that can be found on many contemporary car designs and enables a quicker, more controlled stop.

The ABS system is supported by other safety features including traction control systems and electronic stability control (ESC).

Safety Precautions Before Testing the ABS Module

• Verify that the car is parked on a level surface.
• Place the gearbox in Park or Neutral and apply the parking brake.
• To avoid accidental short circuits, disconnect the negative (-) battery connector.
• As instructed by the manufacturer, raise and support the vehicle.
• Track down the ABS module. On the driver’s side of the car, it is often placed next to the steering wheel.
• Take the vehicle’s ABS module out.
• Inspect for any obvious damage to the module, such as fractures or missing bolts.
• Connect the ABS module to the multimeter.
• Put the multimeter’s “DC voltage” preset in place.

Tools Required To Test ABS Sensor

For all the tests mentioned here, you would need

• Multimeter
• Set of Wrenches
• Car Jack
• OBD Scan Tool

How To Test A ABS Sensor With A Multimeter

The process for testing the ABS sensor is rather simple. To begin with, you must find the sensor. Once you’ve located it, use these procedures to find it on the car’s frame, generally close to the wheel.

Step 1: Lift The Vehicle With A Jack

For safety measures, you activate the emergency brake and park the car’s gearbox for safety purposes to prevent it from moving while you are below it.

Now, you also need to lift the car where the sensor is located in order to get access to it and conveniently conduct a diagnosis on it.

The sensor may be found under one of your wheel hubs depending on your automobile, but you may check your owner’s manual to find out exactly where it is.

You also want to know to prevent confusing the ABS sensor with other sensors, you need also be aware of how the ABS sensor in your car appears. While performing these tests, slide a mat under your car to keep your clothing clean.

Step 2: Set The Multimeter To The 20k Ohms Range

• Set the meter to the Ohms value shown by the omega (Ω ) symbol.
• You will see a group of numbers The measurement range is shown by a set of numbers in the meter’s Ohms section (200, 2k, 20k, 200k, 2m, and 200m).
• To get the most accurate reading, set the meter to the 20k ohm range because it is the typical resistance of an ABS sensor.

Step 3: Disconnect the ABS cable

Now, you disconnect the anti-lock braking system from its sensor cable to expose the terminals for the test.

Here, you simply and gently separate the wire harnesses where they are attached before turning your attention to the harness on the wheel side.

Step 4: Place Probes On ABS Terminals

You can put your meter probes on either of the terminals for the sensor because polarity is irrelevant for measuring Ohms.

Step 5: Evaluate Results

Now, you check the meter’s reading between 800 and 2000 Ohms is typical for ABS sensors.

If the sensor is in good condition, the meter will display a constant value between 0.8 and 2.0 when set to the 20k Ohms range. A number that falls outside of this range or one that changes refers to a defective sensor that has to be replaced.

If you also get an “O.L” or “1” reading, the sensor has to be replaced because its wire harness has a short, break, or too much resistance.

Check the resistance of your abs sensors

You should first check the resistance of your ABS sensors with your multimeter in hand. Turn the multimeter’s ohms () indication on.

Connect the positive probe (red) of your multimeter to the sensor’s positive terminal before touching the negative probe (black) to the sensor’s negative terminal.

The sensor has to be changed if you don’t observe this reading or if the assignment is infinite. Remember that electrical faults might also exist. Make that the sensor has electricity at both terminals by unplugging it from its wire harness (positive & negative).

If both terminals have power, you must investigate the cabling between your sensor and the fuse box (assuming everything else checks out).

Read Also: What Is HFE On A Multimeter

Check continuity in your abs circuit

If you want to check for continuity in your abs circuit, set the diode or wave sign on the multimeter. First, disconnect the negative battery cable. Next, locate the abs sensor and take it out of the car next.

Use the multimeter to check for continuity between the sensor’s two terminals once you have it in your hand. Continuity indicates that the sensor is working. Correctly. A defective sensor has to be replaced if there is no continuity.

A multimeter may be used on each terminal at one end of each terminal to examine if the connections are made, which is another way to verify that the wires are inserted into the correct connectors.

Use a multimeter to check each terminal at both ends of each harness to make sure they are not contacting the ground or shorted to one another anywhere else on the car. If the multimeter displays OL or Open Loop during a continuity test, either the sensor or the wire is defective.

Verify Power

You’ll need to check that the sensor is receiving power and ground. You’ll need to utilize your multimeter to do this. Start by setting your multimeter to the DC Voltage option.

Each metal component of the vehicle connected to the negative battery terminal should have a black probe to the ground. Each cable entering the sensor should be connected to the red probes.

About 12 volts should be seen. If not, there is an issue with the power supply. Check all the fuses in the fuse box under the hood and any loose wires in the wiring harness near the battery connection. Take it to a mechanic for assistance if none of the above solutions are the cause of the lack of power.

Evaluate voltage

Now that the multimeter is connected to the sensor, you may test it. Before touching the probes to the appropriate wires, make sure the multimeter is set to the proper setting.

A measurement of about 5 volts is what you should receive. If not, double-check your connections and your environment. If after, everything seems to be in place, go ahead.

The continuity test is essential because the ECU will detect any breaks in the circuit and enter fail-safe mode if there are any. To do this test, cut one wire from each sensor side, then attach a probe to each end of each wire.

If there are no interruptions in the signal, you should hear a tone right away. If there are no circuit breaks, a tone should sound as soon as you begin testing; otherwise, the circuit is insufficient (wires are damaged).

Conclusion

A multimeter can be used to test the sensor if your car’s ABS is presenting you with a complicated system. There aren’t many tools required for this.

If the multimeter readings fall within the suggested range, the sensor operates properly. But, you might need to replace the sensor if nothing shows up on the screen or you receive an error message.

FAQs