15 Hot Trends Coming Soon About Audi G28 How to Replace an Audi G28 Engine Speed Sensor

In this video, Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the outside of the transmission, above the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49) and then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 through the grey wire. The ECU utilizes this information to control boost and fuel. It also sends an indication to the G5 tachometer in the instrument cluster.

The sensor is used to link the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors according to the situation.

If this sensor fails to function, the ECU will display a P00160 error code. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate a chain stretch or a jumpy chain link in the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).

Testing is a bit challenging as there are two different connector pins and they serve different purposes but the best method of testing it is to measure resistance between the sensor and the ECU. When the sensor is functional, it should read around 1000 ohms. Examine for signs of coolant, or oil in the connector bay if there are issues with this part.

2. Injectors

Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a massive reduction in power. It was like the engine was running out of gas. Or my injectors weren't firing. Today, i pulled out the spark plugs, three were soaked with gazoline and the fourth was dry. I put a piece of tissue over each injector hole, and when I turn the engine on without sparks, the ones with gazoline jump out. The 4th one remains shut. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I get 0ohm. I think the issue is in another location.

I also tried to reset the PID without success. The car will start when the G28 is unplugged and is running fine when it is plugged in but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows a temperature of -49c. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 if i crank up the engine.

I'm not sure what to do. I think I've eliminated everything else. I'm afraid i may have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is identical to the G4 and both function in the 80 100 200, UrS and RS2 cars so you can easily find one at a wrecking yard or at a parts store. It is simple to test them to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines must be aware of the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. In order to do this it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either one of these, the diagnostic scanner will show the codes that could trigger the engine shutting down.

A damaged G28 sensor could result in an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, or a misfire while in gear. If you experience any of these issues, it is most likely that your sensor is failing and should be replaced. The good news is that they are very affordable and easily accessible, especially in the case of the Bosch sensor, which is what ours are. Alternatively, the GM version of this part is also a good choice.

5. Tachometer


A failing engine sensor could cause a number of problems within your vehicle. It's a vital component of the Audi's transmission as it sends information to the ECU about how the car's crankshaft is turning. When advanced key audi G28 Car Keys fails, it can affect the performance of the transmission and the other car's components.

The G5 engine speed sensor is located at the outside of the transmission just above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU is then able to process the signal to control fuel, timig and boost, and also transmitting it to the G5 tachometer inside the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. You should observe around 1000 ohms of resistance between these two points. This is a common component across the Audi 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.