What causes the ABS warning light to stay on in an Audi 80?

My Audi 80 has recently been showing the ABS warning light constantly, even when the car is turned off. What could be the cause of this and how can I fix it?

The most common reason for your ABS warning light staying on is a faulty sensor. This can easily be diagnosed by a mechanic and the sensor can be replaced.

Another possible reason could be low brake fluid levels or a leak in the brake system. It's important to have this checked and fixed as soon as possible to ensure safe braking.

In some cases, dirt and debris can build up on the wheel speed sensors, causing them to malfunction. A simple cleaning can often solve the issue. Try using a toothbrush and brake cleaner to remove any buildup.