How to Replace an Audi G28 Engine Speed Sensor Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is located near the transmission's edge, above the flywheel gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer located on the instrument cluster. 1. Engine Speed Sensor The grey wire is situated at the edges of the transmission, above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends a signal to the G5 tachometer in the instrument cluster. The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft has reached TDC, and the position of the camshaft, in order to activate the spark and injectors. If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and could indicate the chain is stretched or a jump link on the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or G40). It's a bit tricky to test since there are several connector pins, and they all have different functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is in full operation. Examine for signs of coolant or oil in the connector bay if you have issues with this component. 2. Injectors Yesterday, while accelerating from the highway paytoll at a high speed I noticed a massive reduction in power. It was as if the engine had run out of gas. Or my injectors weren't firing. I pulled out the spark plugs this morning, three were drenched in gasoline and the fourth was dry. I put a piece of tissue over each hole in the injector and when I start the engine without sparks, the three with gazoline jump right out. The 4th one stays shut. I