How to Replace an Audi G28 Engine Speed Sensor Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission, above the flywheel ring gear. It sends a signal to the ECU via a grey wire (T55/49) https://g28carkeys49658.activablog.com/29356488/10-places-to-find-audi-a1-key