How to Replace an Audi G28 Engine Speed Sensor Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge over the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer https://autolocksmiths04400.jts-blog.com/29519015/this-is-what-audi-a1-key-will-look-like-in-10-years-time