How to Replace an Audi G28 Engine Speed Sensor Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is located near the edges of the transmission above the flywheel ring gear. It sends a message to the ECU via the grey wire T55/49 https://g28-car-key-solutions49456.theisblog.com/30066019/this-is-how-audi-a1-key-will-look-in-10-years-time