If the warning light on an anti-lock brake system stays on while the vehicle is moving, what could be the cause?

The presence of a warning light on the anti-lock brake system (ABS) while the vehicle is in motion indicates that the system has detected an issue that requires attention. One common cause for this warning light to remain illuminated is a mis-adjusted wheel sensor. The wheel speed sensors play a critical role in monitoring the speed of each wheel and help the ABS module determine when to activate the anti-lock function to prevent wheel lockup during hard braking.

If one of these sensors is misaligned or improperly adjusted, it may not provide accurate readings to the ABS module. Inconsistent or erroneous data from the wheel sensor can lead to the ABS system thinking there is a fault, causing the warning light to activate. Consequently, proper alignment and adjustment of the wheel sensors are vital for the system's functionality and to ensure that warning lights do not indicate false issues.

In comparison, while a bad air release solenoid, a blown fail-safe monitor fuse, and a faulty warning light relay can all potentially cause issues in the braking system or warning light functionality, they are less directly related to the ongoing operation of the ABS while the vehicle is moving. A malfunction in these components may lead to other types of failures or warning signals, but a mis-adjusted wheel sensor is the