Why Nobody Cares About Audi G28

How to Replace an Audi A1 keys G28 Engine Speed Sensor

In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located near the edges of the transmission above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire (T55/49), then to the tachometer within the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, just above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to control boost and fuel. It also sends an indication to the G5 Tachometer located in 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 so it can trigger spark and injectors in the right way.

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

Testing is a bit tricky because there are two pins for the connector and they have different functions however the best way to test it is by measuring resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading about 1000 ohms. Examine for signs of coolant or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced massive power loss like the engine is running out of gas or the injectors are not firing anymore. I took out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was unclean. 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 4th one stays closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero Ohm. Therefore, i think the issue is somewhere else.

I also tried to reset PID but without success. The car is able to start if the G28 is disconnected and runs fine when it is plugged in however it has the intermittent misfire issue at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature of -49c even when i unplug it. Also, i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.

I'm not certain what to do, as i think i've pretty much completely ruled out all other possibilities. However, i'm afraid that i might have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter 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 junkyard or in a local parts store. It is simple to test them by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that has to know the position and speed of the crankshaft in order to make decisions about fuel injector timing etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, replacement Audi car Key the diagnostic scanner will show codes that could lead to an engine shut down.

The signs of a failed G28 sensor include an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or misfiring when in gear. If you have any of these issues it is likely your sensor is failing and requires replacement. They are cheap and easy-to-find particularly when they're a Bosch sensor like ours. Alternatively, the GM version of this part is also a good option.

5. Tachometer

A faulty engine speed sensor could be the cause of many problems in your car. It's an essential component of the audi replacement key fob's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. When this sensor fails, it can cause problems for the transmission as well as the rest of the car's components.

The G5 engine speed sensor is located at the edge of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49, via an uncolored wire. The ECU uses this signal to regulate the flow of fuel and boost and also to timigrate. It also sends it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity from 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 observe approximately 1000 ohms resistance between those two pins. This is a common feature across the audi tt key programming 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 Du, so you might find them in wrecking yards.