How to Replace an Audi G28 Engine Speed Sensor Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It sends a message to the ECU via a grey wire T55/49, https://carlocksmiths21334.answerblogs.com/30346995/10-places-to-find-audi-a1-key