What does the ABS sensor do?

The ABS sensor is used to monitor wheel speed and rotation, as part of the wider anti-lock braking system. The data it gathers is sent to the ABS control module, which in turn determines how much pressure to apply.

Can I drive with a bad ABS sensor?

You can still drive with a bad ABS sensor, but given it works as part of a key safety feature, it should ideally be replaced at the earliest opportunity.

Why do ABS sensors fail?

An ABS sensor can become faulty if its wires are damaged, or the sensor is covered in debris.

Is a faulty ABS sensor an MOT failure?

A faulty ABS sensor can result in the ABS warning light turning on; this is typically an MOT failure.