In addition, each of the four wheels has a wheel-speed sensor.Checked 2026-08-16
Wheel-speed sensor
A sensor at each wheel that reports rotation speed to ABS, stability-control and related systems.
Also called: ABS sensor · wheel sensor · speed sensor · tone ring · encoder ring
What it means
Definition
A wheel-speed sensor reads a toothed or magnetic encoder as the wheel turns and sends a speed signal to the vehicle’s control systems. ABS compares those signals to detect wheel slip; stability and traction systems use the same information alongside other sensors.
Why a buyer cares
What it changes
A failed wheel-speed signal can switch off ABS, traction control and stability control together even though the base brakes still operate. The sensor, its wiring and the encoder or bearing are separate possible causes.
In practice
Where you meet it
In ABS trouble codes and estimates naming a wheel-speed sensor, tone ring, encoder ring or hub bearing.
Two things that look alike
Not the same as
The vehicle-speed reading can be calculated from wheel signals, but a wheel-speed sensor reports one wheel rather than road speed by itself.
Read next
Related terms
Anti-lock Braking System (ABS)
The part of the brake system that controls wheel slip during braking so the wheels do not lock.
Electronic Stability Control (ESC)
A system that brakes individual wheels to correct the vehicle's direction during a skid.
Wheel bearing and hub
The low-friction bearing and hub assembly that supports the wheel while allowing it to rotate.
Diagnostic Trouble Code (DTC)
The code an OBD-II system stores to identify which monitored system it found a fault in.
Where this comes from
Sources
Sensors continuously monitor the speed of each wheel.Checked 2026-08-16
Sensor and encoder construction vary, and some vehicles derive additional functions from the same signal.