Notes

Responsible For The Audi G28 Budget? 10 Unfortunate Ways To Spend Your Money
How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This sensor is situated on the outside of the transmission, above the flywheel gear. It transmits a signal to the ECU via a grey wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated on the outside of the transmission, just above the flywheel ring. This sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to control the amount of fuel and boost. It also sends an alert to the G5 Tachometer in instrument cluster.

The sensor is used to link the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC and also the position of the camshaft, to trigger the spark and injectors.

If this sensor fails, the ECU will show an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper timing 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 since there are different connector pins, and they all have different functions. lost my audi car keys for doing this is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms when it is operating at its maximum. Examine for signs of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, when accelerating from highway paytoll at maximum speed, i noticed a huge decrease in power. It was as if the engine had run out of gas. Or my injectors were not firing. This morning i pull out the spark plugs. Three were drenched with gazoline the 4th one was dry. I placed a tissue over each injector hole, and when I start the engine with no sparks, the 3 with gazoline jump right out. The fourth one remains shut. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero Ohm. I think the issue is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it is running fine with the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.

I'm not sure what to do, i feel i have pretty much eliminated everything else. However, i'm afraid that I might have missed something. If anyone has any 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 identical to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or a parts store. It is simple to test them - simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.


4. ECU

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

The signs of a failed G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal and/or misfiring when in gear. It is possible that your sensor is failing and needs to be replaced if you encounter any of these symptoms. The good thing is that they are very affordable and easy to find particularly when you're looking at a Bosch unit which is what we have. Alternatively, the GM version of this unit is also a good option.

5. Tachometer

A failing engine speed sensor could be the reason behind many issues in your vehicle. It's a crucial component of the transmission of your Audi because it relays information to the ECU about how fast or slow the engine of the car is spinning. If this sensor fails, it can cause problems for the transmission as well as the other car's components.

The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU uses this signal to regulate fuel and boost, as well as timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Also, you can examine the continuity between pins 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 observe approximately 1000 ohms resistance between those points. This is a common feature across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and 1995 RS2 DU So, you may find some good ones in wrecking yards.

Website: https://notes.io/w2YyH