The next step after cutting power to reset the ECU (if that doesn't fix it) is to reset the yaw sensor.
I'll just suggest that, while there are a few causes for this that are mechanical issues or failing sensors, don't forget to check the sensor wires. I had this problem, somehow the wire to one of the rear wheel speed sensors got cut or otherwise damaged. That's kind of an oddball problem, but cheap & easy to fix.
You can repair the wires and reset the yaw sensor, even though the dealer would claim that the whole sensor wire will have to be replaced for lots of $$$. Not true, I'm pretty sure they're active speed sensors with digital signal, so changing the impedance of the wire a tiny bit through a repair isn't going to matter much.
