By Larry Carley
Technical Editor

Wheel speed sensors (WSS) provide essential wheel speed information not only for anti-lock brake systems (ABS), but also for traction control and stability control systems. Some vehicles even compare the wheel speed sensor readings against the vehicle speed sensor (VSS) to make sure all of these sensors are accurate and working correctly.

In some situations, it is also possible that the signal from a WSS may not be bad enough to set a fault code, but may be off enough to upset the normal operation of the ABS, traction control or stability control systems. This might be the result of an intermittent signal or a noisy signal that is confusing the system control module.

On older ABS systems, a fault code is typically set if there is a loss of a signal in a WSS circuit (shorted or open), or the reading from one WSS sensor differs significantly from the rest. On some newer vehicles, “plausibility” codes may also be set if the speed reading of any WSS sensor differs from the vehicle speed sensor by more than 3...