What The Heck Is Audi G28

How to Replace an audi remote key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates 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) and then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The sensor is located at the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 via the grey wire. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an indication to the G5 tachometer inside the instrument cluster.

The sensor is used to connect 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 according to the situation.

If this sensor fails, the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync and could indicate the chain is stretched or a jump link on the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).

Testing can be a bit difficult as there are two different connector pins and they perform different functions but the most effective way to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms when it is operating at its maximum. If you are having problems with this component, look for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had massive power loss like the engine is running out of gas or the injectors aren't firing anymore. This morning i pull out the spark plugs, 3 were drenched in gazoline, the 4th one was dry. When I start the engine with no sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline jump out but the 4th stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found zero ohm. So i assume the problem is somewhere else.

I also tried to reset the PID but without success. The car will start if the G28 is unplugged and it runs perfectly when it is connected however it is experiencing intermittent misfires at higher RPM. The coolant temperature sensor (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 while the actual pressure is 0.0 if i crank up the engine.

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

3. Fuel Pump

The fuel pump in the g28 gets a signal 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 a spare in a wrecking shop or a parts store. It is simple to test them - just put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that must know the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, for example. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you are experiencing issues with either one of these, the diagnostic scanner will show codes that could lead to the engine shutting down.

A failing G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts more quickly than normal, and/or an unfire when in the gear. It is likely that your sensor is failing and requires to be replaced if you experience any of these symptoms. They're cheap and easy to find, especially if they're a Bosch unit like ours. Alternatively, GM's version of this part is an excellent choice.

5. Tachometer

A failing engine sensor could cause a myriad of issues in your audi car keys replacement. It is an important part of the transmission in your audi new key because it relays information to the ECU on how fast or slow the car's engine is turning. If this sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.

The G5 engine sensor is located at the outskirts of transmission, above the flywheel ring. It sends an electrical signal through a gray wire to the ECU pin T55/49. The ECU then processes the signal to control fuel, timig and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. You can also 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 and pin T26a/12. It should show approximately 1000 ohms resistance between those points. This part is common across the audi a5 Key fob 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 Du, so you might find some good ones in wrecking yards.