Thought about replying back to your email but in case your NSX is still at the shop, I wanted to show some respects to the people diagnosing the issue for you so decided to reply through here than behind the scene.

VSS is a very simple circuit. Also, being as a Japanese production car, the spec of VSS frequency is specified by JIS so regardless of the car maufactures, wheel diameter, etc, it will follow that spec.


VSS on our NSX is just three wires.
12V power supply, GND and the VSS output. It will be 0 -> 5V square wave form.
It's driven by the thin metal ring on the DF body so you need to lift up the rear of the car and rotate the wheel with your hand.
As your NSX is with the electronics engineers, it's quite easy to test.

Not sure exactly what kind of issues you are having but did you get multiple warning lights for the VSS?
VSS is shared with many devices such as ECU, EPS, AT controller, Cruise control, etc so if you have VSS failure, you will not only have speedo issue but also CEL and other warning lights will be triggered depending on the spec of your NSX. Best to read the error code first.


Kaz