This describes what I found when I took the "servo" apart. (I got it back together with much struggling so this is from memory.)

It has 2 wires that go to the motor and 4 wires that go to some kind of rotating position sensor. On a small board are 2 etched concentric circles which are in contact with a 4-pronged device mated to the spinning gear. I think 2 of
the 4 prongs touch the outer circle, the other two the inner circle.

Have any of you come across such a device? Any idea its purpose and how I control it. Other cheap cars just go bang bang into the steering motor with a little spring plus the caster effect to bring it back to neutral.

Ken