Why No One Cares About Audi G28

How to Replace an audi key copy 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 sends a signal to the ECU via an uncolored 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 using the grey wire. The ECU uses this information to regulate boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.

If this sensor key Audi fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate a chain stretch or a jump in the chain link of the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).

It is a little tricky to test as there are various connector pins, and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should read around 1000 ohms. Look for signs of coolant or oil in the connector bay if there are problems with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a significant decrease in power. It was as if the engine had run out of gas. Or my injectors were not firing. In the morning, i removed the spark plugs. Three were drenched in gazoline, the fourth one was dry. When I crank the engine without sparks, i place a tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. I'm assuming that the issue is elsewhere.

I also tried to reset PID but without success. The car is able to start if the G28 is not plugged in and is running fine when it is connected, but still has the intermittent misfire issue at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.

I'm not sure what to do. I think I've ruled everything else out. I'm worried that i might have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. It is simple to test them - simply switch 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 should be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines must know both the speed and position of the crankshaft to determine timing of fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.

Some of the symptoms of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or Audi Advance Key a misfire when you are in gear. It is possible that your sensor is failing and needs to be replaced if you experience any of these signs. The good news is that they are very affordable and readily available particularly when you're looking at the Bosch model, which is what ours are. You can also choose the GM version of this unit is also a good option.

5. Tachometer

A malfunctioning engine speed sensor could be the cause of a slew of problems in your vehicle. It's a vital component of the audi a3 key fob replacement's transmission since it relays information to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor can cause the transmission to fail and other components in the car to be affected.

The G5 engine speed sensor is situated on the outside of the transmission above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49, via an uncolored wire. The ECU is then able to process this signal to regulate fuel, timig, and boost and then transmitting it to the G5 tachometer in the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 and pin T26a/12. You should see approximately 1000 ohms of resistance between those two pins. This part is common across the audi a3 keys 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN and 1995 RS2 DU You may also find them in wrecking yards.