Active vs Passive Wheel Speed Sensors (VIDEO)

Active vs Passive Wheel Speed Sensors (VIDEO)

The difference lies in how the sensors measure wheel speed. This video is sponsored by BCA Bearings.

Before you can diagnose a suspected faulty wheel speed sensor, you need to have a good understanding of the type of sensor you’re working on and how it functions. There are two different types of wheel speed sensors – Active or passive. There is no way to visually identify which type of sensor you’re dealing with. OE service information won’t specify the sensor type, and neither will the DTCs.

Passive Wheel Speed Sensors

Passive wheel speed sensors are two-wire permanent magnet sensors. They produce an AC voltage signal which is generated when a toothed tone ring or reluctor passes by the sensor. This reluctor may be part of the CV axle or wheel bearing assembly.

To test the sensor, disconnect the harness and use a DVOM to measure the AC voltage generated by the sensor as you spin the wheel by hand. You should see a reading of around 0.5-1.0 volts. The faster the wheel spins, the higher the voltage output.

Some passive sensors may receive DC voltage through the ground wire from the ABS module. To test this type of sensor, disconnect the sensor and backprobe the positive lead to the signal wire and the negative lead to the other side. This voltage comes directly from the ABS module and should be between 1.5 and 5 volts.

Active Wheel Speed Sensors

Active wheel speed sensors used to look the same as passive sensors, but they are much more accurate at lower speeds. Active sensors output a digital signal, a DC square wave signal. To test this type of sensor you’ll need a scan tool which can communicate with the ABS module, or a DVOM which can graph a digital voltage signal.

Active vs. Passive: Real World Example

Let’s look at a real word example of why it is so important to identify which type of sensor you are working with, the 2007 model year Chevy Silverado and GMC Sierra. In this single model GM produced two different platform trucks, the GMT 800 platform trucks which came with passive sensors and the GMT 900 platform trucks which came with active sensors. If you were working on one of these very common trucks, you would need to know more than just the year, make, model to determine which type of sensor you are working with.

This video is sponsored by BCA Bearings.

You May Also Like

Limited Slip Supplement (VIDEO)

If the frictional properties are not correct, chatter will occur. Sponsored by Lubegard.

Welcome to the Lubegard Limited Slip Supplement overview. Clutch-based limited slip differentials are common on many automotive applications like trucks and SUVs, but they present a unique problem. These differentials often use different clutch configurations, either cone or flat type, made with various materials and frictional requirements. When both wheels have ample traction, the clutch plates bind together tightly, sending consistent power to each wheel. When one wheel slips, additional power is sent to the other wheel based on the frictional properties of the clutch packs. This is where the gear lubricants frictional properties play an important role in functionality and performance.

Rust and Corrosion Preventive Oil (VIDEO)

Your tools and equipment need to be protected from rust. This video is sponsored by Lubegard.

Auto Pros Team Visits Hybrid Shop of The Carolinas

Auto Pros on the Road puts the Babcox team into shops across the USA. This episode is sponsored by Autolite.

Nissan Around View ADAS Camera Calibration (VIDEO)

Always calibrate the around view monitor system after a collision.This video is sponsored by Hunter Engineering.

Collision Blueprinting with Alignment Equipment (VIDEO)

An alignment is usually called for prior to ADAS calibrations. This video is sponsored by Hunter Engineering.

Other Posts

ADAS Calibrations: Accessing the FCA/Stellantis Secure gateway

The secure gateway ensures no procedures are performed without the proper data. Sponsored by Hunter Engineering.

Ford F-250 Shock Replacement (VIDEO)

Follow along the step by step installation process of shocks on a Ford F-250. This video is sponsored by PRT.

2007-2021 Toyota Tundra Strut Replacement (VIDEO)

Follow along the step by step installation process for struts on 2007-2021 Toyota Tundra’s. This video is sponsored by PRT.

AMN Drivetime: MEMA Leaders Chat About The Future

MEMA leaders sat down with Bill Babcox to share a few updates on the realignment of the association announced in November.