The Most Innovative Things Happening With 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 at the edge of transmission over the flywheel gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer 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 a signal via the grey wire to pin T55/49. The ECU uses this information to regulate fuel and boost. It also sends a signal to the G5 Tachometer located in the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.
If this sensor fails, the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper chain of timing. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing can be a bit difficult because there are two connector pins, and they have different functions however the best method of testing it is by measuring resistance between the sensor and the ECU. If the sensor is functional, it should read approximately 1000 ohms. If you're experiencing issues with this component, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed, i noticed a huge drop in power. It was like the engine had run out of gas. Or, my injectors weren't firing. In the morning, i removed the spark plugs. Three were soaked with gazoline and the fourth one was dry. I put tissue over each injector hole, and when I start the engine with no sparks, the three with gazoline jump out. The 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. I think the issue is in another location.
I also tried to reset the PID with no success. The car will start when the G28 is disconnected and it runs perfectly when it is connected but it still has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of -49c, even if I unplug it. I also noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev the engine.
I'm not sure what to do, as i believe that i've ruled out everything else. I'm afraid i may have missed something. If anyone has any suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate the spare in a salvage shop or parts store. It is easy to test them: simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that must be aware of the speed and position of the crankshaft in order to make decisions about timing of the fuel injectors, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will display codes that could lead to an engine shut down.
Some of the signs of a malfunctioning G28 sensor are an inaccurate rev counter for the gearbox the gears are shifting faster than normal, and/or a misfire when in gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these symptoms. The good news is that they are very affordable and readily available particularly in the case of a Bosch model, which is what ours are. If you prefer, GM's version of this part is an excellent choice.
5. Tachometer
A failing engine speed sensor could be the cause of numerous problems in your vehicle. It is an important part of the transmission of your Audi because it relays information to the ECU on how fast or slow the engine of the car is spinning. If the sensor fails, it could affect the performance of the transmission, as well as the rest of the car's components.
The G5 engine speed sensor is located on the edge of the transmission just above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 through a grey wire. The ECU uses this signal to control fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer inside the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should observe approximately 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. replacement audi key could be available in wrecking yards.