How To Beat Your Boss 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 edge of transmission, above the flywheel gear. It transmits a signal to the ECU through an uncolored wire T55/49, then to the tachometer in 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 signals to ECU pin T55/49 via the grey wire. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.

The sensor is used to link the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors in the right way.

If this sensor fails to function, the ECU will display a P00160 error code. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jump in the chain link of the upper chain. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).

It's a bit tricky to test as there are different connector pins, and they all have different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is fully functional, it should read approximately 1000 ohms. If you're experiencing issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed I noticed a significant drop in power. It was like the engine had run out of gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the fourth was dry. I put a piece of tissue over each hole in the injector and when i start the engine with no sparks, the three with gazoline jump right out. The 4th one remains closed. I tested the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. I'm assuming that the issue is in another location.

I also tried to reset PID without success. The car can start when the G28 is disconnected and runs fine when it is connected but it still has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c even when i unplug it. Also i noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do. I believe that I've all other possibilities out. But i'm worried that I might have missed something. If anyone has suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style sender is the same as the G4 and they both work in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or in a local parts store. Test them out - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black end of the connector). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines must be aware of the position and speed of the crankshaft to make decisions regarding fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either of these, the diagnostic scanner will display the codes that could trigger an engine shutdown.

A damaged G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts more quickly than normal, and/or a misfire while in the gear. If you are experiencing any of these issues it is most likely that your sensor is deteriorating and should be replaced. They are cheap and easy-to-find, especially if they're an Bosch model like ours. Alternatively, the GM version of this component is also a good choice.

5. Tachometer

A failing engine speed sensor could be a cause for numerous problems in your car. It's a crucial component of the transmission of your audi smart key replacement, as it transmits information to the ECU on how fast or slowly the engine of the replacement car key audi is turning. This sensor could cause the transmission to fail and other components in the car to be affected.

The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU then uses and processes the signal to control fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can test for sensor failure by examining the continuity from the sensor to the tachometer. Also, 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 as well as pin T26a/12. You should see an average resistance of 1000 ohms in these areas. This is a standard part that is found across the audi a5 key fob 80 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good parts could be found in wrecking yards.