I was tring to find some troubleshooting info on my TX 66 beater sensor and stumbled across your post. It was very helpful indeed. Now I am hoping you might be able to help me a little more. The brown wire is gounded to the frame and the voltage at the plug blue wire is around 8 volts. I have installed a new sensor but the the red light still stays on when the machine is running at full speed. I do not know how to access the error messages but any additional info would be greatly appreciated.