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What NOT To Do With 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 located at the top of the transmission, above the flywheel ring gear. It transmits a signal the ECU via an uncolored wire (T55/49), then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission above the flywheel ring gear, the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using an uncolored wire. The ECU utilizes this information to regulate boost and fuel. It also sends signals to the G5 Tachometer located in the instrument cluster.

The sensor is used to connect with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can activate spark and injectors accordingly.

If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is out of sync with the Intake Camshaft. audi key could also be a sign of an issue with the chain or a jumped chain link in the upper chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).


It is a little tricky to test because there are various pins on the connector, and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when it is operating at its maximum. Look for evidence of coolant or oil in the connector bay if you are experiencing issues with this component.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. I put a piece of tissue over each injector hole and when i start the engine with no sparks, the three that have gazoline pop right out. The 4th one stays shut. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero ohm. Therefore, i think the issue is elsewhere.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged and runs fine when it is plugged in however it has intermittent misfire issues at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.

I'm not sure what to do. I believe that I've all other possibilities out. But i am afraid I might have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or a parts store. Test them out 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 should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines requires to know both the position and speed of the crankshaft in order to make a decision about timing of the fuel injector, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which can cause the engine to shut down.

A malfunctioning G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, and/or an unfire when in the gear. It is possible that the sensor is failing and needs to be replaced if you encounter any of these symptoms. They're inexpensive and easy to locate, especially in the case of a Bosch sensor like ours. If you prefer, GM's version of this component is an option.

5. Tachometer

A damaged engine sensor could cause a number of problems within your vehicle. It's a vital component of your Audi's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is spinning. When this sensor fails, it will disrupt the performance of the transmission, as well as the rest of the car's components.

The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU then processes the signal to control fuel, timig, and boost and then transmitting it to the G5 tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can check continuity between pin 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 see approximately 1000 ohms resistance between those points. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 Du, so you might find some good ones in wrecking yards.