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How to Replace an audi replacement keys G28 Engine Speed Sensor

Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor Audi Car Key Cover is located near the transmission’s edge over the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the edge of transmission, above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.

The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors accordingly.

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

It’s a bit tricky to test as there are different connector pins, and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. If the sensor is operational, it should be reading about 1000 ohms. Check for evidence of coolant or oil in the connector bay if there are issues with this component.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed I noticed a massive reduction in power. It was as if the engine was running out of gas. Or my injectors were not firing. I took out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. When i crank the engine with no sparks i put tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th stay shut. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I’m assuming that the issue is in another location.

I also tried to reset the PID without success. The car can start if the G28 is not plugged in and is running fine when it is plugged in however it has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value 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 0.

I’m not certain what to do, i believe that i’ve eliminated everything else. I’m afraid i may have missed something. If anyone has any suggestions, please chime in! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or parts store. Testing them is easy to do – just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector’s side up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY) engines must know the position and speed the crankshaft to make decisions regarding timing of fuel injectors, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these, the diagnostic scanner will display codes that could lead to an engine shut down.

The signs of a failed G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal, and/or a misfire when in gear. It is possible that the sensor is failing and requires to be replaced if you encounter any of these symptoms. They’re cheap and audi car key cover easy to find, especially in the case of a Bosch sensor like ours. You can also choose the GM version of this component is also a great option.

5. Tachometer

A failing engine sensor could cause a myriad of issues within your vehicle. It’s an essential component of the transmission in your Audi since it sends information to the ECU on how fast or slow the engine of the car is spinning. 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 the transmission, over the flywheel ring. It transmits signals via an uncolored wire to the ECU pin T55/49. The ECU then uses and processes this signal to regulate the flow of fuel, timig and boost, and also transmitting it to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms of resistance between these two points. This is the same across the audi car key Cover 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 Du So, you may find good ones in wrecking yards.