How to troubleshoot a faulty ABS sensor on an Audi A5?

I've recently noticed that my Audi A5's ABS light is constantly on. I suspect that one of the ABS sensors may be faulty. How can I test and troubleshoot the sensor to determine the issue and fix it?

First, you can try using a diagnostic tool to check for any trouble codes related to the ABS system. If that doesn't yield any results, you can use a multimeter to test the resistance of each ABS sensor and compare them to the manufacturer's specifications.

Another common issue with ABS sensors is dirt or debris buildup that can interfere with their readings. Try cleaning the sensor and the surrounding area before testing it again.