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What NOT To Do During The Audi G28 Industry
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 situated near the transmission's edge, above the flywheel gear. It transmits a signal the ECU via the grey wire (T55/49) which is then sent to the tachometer located in 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 signals to ECU pin T55/49 using an uncolored wire. The ECU utilizes this information to regulate fuel and boost. It also sends signals to the G5 tachometer inside the instrument cluster.

The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must be aware of when the crankshaft has reached TDC and also the location of the camshaft in order to activate the spark and injectors.

If this sensor fails, the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and could indicate chain stretch or a jumped link on the upper chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).

Testing is a bit tricky as there are two different pins for the connector and they perform different functions but the most effective way to test it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms when it is in full operation. Examine for signs of coolant, or oil in the connector bay if you are experiencing issues with this component.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a massive decrease in power. It was as if the engine had run out of gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, three were drenched in gasoline and the fourth was unclean. When I crank the engine without sparks, I put a piece of tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stay shut. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 I got zero Ohm. I assume that the problem is somewhere else.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 plugged in. However the intermittent misfire issue still occurs at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c, even if I unplug it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when I crank up the engine.


I'm not sure what to do, i feel i have pretty much eliminated everything else. But i'm worried that I might have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. audi replacement key cost uk TheKeyLab -style transmitter functions similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. It is simple to test them by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that needs to know the speed and position of the crankshaft in order to make decisions regarding fuel injector timing etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go bad you will get codes on the diagnostic scanner which could cause engine shut down.

The signs of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or a misfire when in gear. If you have any of these issues, it is most likely that your sensor is deteriorating and requires replacement. The good news is they are very affordable and easily accessible particularly when you're looking at the Bosch model, like ours. Alternatively, GM's version of this part would be a good option.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of a slew of problems in your car. It is an important part of the transmission of your Audi, as it transmits information to the ECU on how fast or slowly the car's engine is turning. If the sensor fails, it can disrupt the performance of the transmission, as well as the other car's components.

The G5 engine speed sensor is located at the edge of the transmission, above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via a grey wire. The ECU then processes this signal to regulate the flow of fuel, timig and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by checking continuity from the sensor to the tachometer. Additionally, you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 and pin T26a/12. You should detect the resistance to be around 1000 ohms between these points. This part is common across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS An and 1995 RS2 DU You may also find good ones in wrecking yards.