Your simple, dandy observation indicates everything is okay electrically. Broken wires to wheel speed sensors and other components would show up right away during the initial six-second self test, then the yellow warning light would not turn off at all. The ABS computer is detecting a problem that is mechanical in nature, and only shows up when the wheels are rotating. The typical suspect is the signal is missing from one speed sensor or it is too weak for the computer to read. All speed sensor signals get weaker at slower speeds.
The place to start is by reading and recording the diagnostic fault codes. This probably can't be done for free by the people at the auto parts stores, but you can ask anyway. Most of them can only read fault codes in Engine Computers. You most likely will have to use a scanner that can access your ABS computer.
Friday, February 26th, 2021 AT 10:59 AM