The 10 Most Scariest Things 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. The 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) and then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using a grey wire. The ECU uses this information to regulate fuel and boost. audi tt keys sends signals to the G5 tachometer in the instrument cluster.

The sensor is used to connect with 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 start spark and injectors according to the situation.

If this sensor fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jumpy chain link in the upper timing chain. However, the error code won't appear on its own without additional information from other sensors (G4 and G40).

Testing is a bit challenging because there are two pins for the connector and they have different functions but the most effective way to test it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is operating at its maximum. Look for evidence of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, i experienced a big cut in power as if the engine was running out of gas or injectors aren't firing any more. I took out the spark plugs this morning, three were drenched in gasoline and the fourth was unclean. I placed a tissue over each hole in the injector and when I start the engine with no sparks, the ones with gazoline jump out. The 4th one remains closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. I think the issue is in another location.

I also tried to reset PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice temperature of -49c. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.


I'm not sure what to do, but i feel i have pretty much eliminated everything else. I'm afraid i may have missed something. If anyone has suggestions, please let me know! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or parts store. It is easy to test them: simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). genuine audi key replacement uk must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines needs to know the position and speed of the crankshaft to make decisions regarding fuel injector timing, etc. To accomplish genuine audi key replacement uk , it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these sensors, the diagnostic scanner will show codes that could cause the engine shutting down.

The signs of a failing G28 sensor are an inaccurate rev counter for the gearbox and gears that shift faster than normal, and/or a misfire when in gear. It is likely that your sensor is failing and needs to be replaced if you encounter any of these symptoms. The good news is they are very affordable and easy to find, especially when you're looking at a Bosch unit which is what ours are. Alternatively, GM's version of this part would be an excellent choice.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of a slew of issues with your car. It's an essential component of the Audi's transmission as it sends information to the ECU about how the car's crankshaft is spinning. If the sensor fails, it can disrupt the performance of the transmission, as well as the rest of the car's components.

The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear. It sends 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 sends it on to the G5 tachometer inside the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe around 1000 ohms of resistance between those points. This is a typical part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.