How do I troubleshoot the ABS system on my Audi 80?

I am seeing the ABS warning light on my Audi 80 dashboard, how can I diagnose and fix this issue?

Check the brake fluid levels and make sure they are at the proper level. Low brake fluid can trigger the ABS warning light. If needed, top off the fluid and see if the light goes off.

Inspect the ABS sensors on each wheel to make sure they are clean and free of debris. Dirty sensors can cause the system to malfunction. Use a small brush to clean the sensors.

Reset the ABS system by disconnecting the battery for a few minutes and then reconnecting it. This can often clear any stored error codes and fix the issue. Make sure to also check for any visible damage to the ABS system components while the battery is disconnected.