How to Test a Speed Sensor with a Multimeter

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How to Test a Speed Sensor with a Multimeter

Speed sensors are usually located on the wheels of your car, and they perform the function of reading the overall number of wheel rotations and then delivers you the information. So how do you test the wheel speed sensors? Well, you can easily do this using a multimeter, and consequently, you will be able to tell whether there is any malfunction to make the needed repairs.

Therefore, if you are looking to know how to use your multimeter to test a speed sensor, read through this article as you get to gain this valuable insight into the steps you need to follow. Subsequently, you will be in a better position to track the speed sensor’s speed, thereby get to drive meticulously.

Prep your car

When testing the speed sensors, you need to first prepare your vehicle by setting it on level ground and then switching off its engine. After that, make use of the transmission usually located in the park settings together with the emergency brake.

Consequently, lift your car using a jack to remove its tires. Doing this enables you to test the sensors, thanks to your car’s ideal position. Some of the essential tools you need to test the speed sensor include;

  • Multimeter
  • Floor jack
  • Car manual
  • Torque wrench
  • Flying leads
  • Tire iron
  • Assistant
  • Jack stands

Once you confirm you have all the essential equipment, you can then go right ahead and test the speed sensor, following the steps below in order.

Remove the connector

After placing your vehicle in a high position using a jack and the wheel is removed, you can now head to the wheel speed sensor. At this point, you should inspect and try to find the electrical connector located close to the wheel’s frame. Consequently, take off the sensor wire by unlocking its safety clasp and then pulling it away gently, and you will see the speed sensor terminals needed for testing.

Use your multimeter

Now that the speed senor terminals are exposed, you can then go ahead and use your multimeter. To do this, make use of the probes integrated into the design of your multimeter and attach them to the speed sensor terminals. Moreover, use alligator clips that typically go together with the multimeter to fasten the speed sensor firmly.

As you attach the speed sensor terminals to do the test, ensure the probes never come into contact with each other because doing so causes the fluctuation of the readings. By doing this, you will generally have an easier time testing your speed sensor.

Once you have confirmed that the terminals and probes are correctly connected, you then need to switch on the AC voltage. Consequently, you will instantly see the multimeter showing the readings up and down, with this a clear sign that you can now test the speed sensor.

Carry out the test with your multimeter

You now can go ahead and take the readings from your multimeter, and to do this, you need to spin the hub or wheel, with the reading varying depending on the wheel’s speed. The readings consequently display on the meter and fall to zero when the wheel stops spinning.

If the multimeter is showing any readings while the wheel is spinning, this is a sign that the sensor is functional. Nevertheless, when no reading is being displayed regardless of whether the wheel is spinning or not, this is an indication the speed sensor has failed and needs to be replaced.

Replace the speed sensor

If the multimeter shows no readings, you should then go right ahead and get another speed sensor. Therefore, you should take off the damaged ones by going to the clips or nuts that are holding the speed sensor in place and loosen them gently. Eventually, the sensor will detach from your car, thereby allowing you to remove it.

With the old sensors out, you then need to put in place the new and functional sensors. Nevertheless, you need first to inspect the area for any sign of rust, and after that, make use of sandpaper to scrub the surface that you intend to install the new sensor.

After the new sensor is in place, use clips or crews to tighten it and then test using your multimeter whether any readings are being displayed when the wheel is spinning. You should also put back the rotors as well as brake pads if you had removed them to get a better view of the sensor.

However, if the multimeter still does not show any readings, you then need to replace it. You should then return everything to its original place in an organized manner. Subsequently, after you are done with the sensor parts and brake pads, you should go ahead and restore the wheel on the hubs. Moreover, make sure everything fits perfectly and then make use of a ratchet and socket to tighten the lug nuts.

You should then use the jack to gradually lower your car back to its original position by making use of the jack stand. Once you are done, use the lug nuts to fix the wheels to your vehicle and then use nuts to tighten them firmly with your hands.

Consequently, make use of a torque wrench that is set to your vehicle’s torque capacity, and this value is usually found on the car’s user manual. Go ahead and put in place the nuts firmly and securely making use of the torque wrench, and this should take you about one or two minutes.

Conclusion

If you were looking to learn how to test a speed sensor with a multimeter, you now have an idea of what to do. Therefore, you never have to worry about not knowing the speed at which you are driving with this vital for improving your safety while on the road.

However, once you are done testing the sensor using the multimeter, you always need to perform a test drive to confirm that everything is working as required. Once you are confident that everything is working fine, you can go ahead and use your car without any concerns about your safety on the road.

About the Author Dan

Just a random guy who likes to build things. Providing tool knowledge, appliance/device testing tips, and DIY project info in an easy-to read & non-intimidating style.