How to Replace an audi Key blade G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the outside of the transmission, above the flywheel gear. It sends a message to the ECU through the grey wire T55/49 and then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

The grey wire is situated at the edges of the transmission, directly above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and New audi Key timig. It also sends an alert to the G5 Tachometer in instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors in the right way.

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 will not be displayed on its own without additional information from other sensors (G4 and G40).

Testing is a bit tricky as there are two different connector pins and they serve different purposes however the best way to test it is to measure resistance between the sensor and the ECU. If the sensor is functional, it should read around 1000 ohms. Examine for signs of coolant, or oil in the connector bay if you are experiencing issues with this component.

2. Injectors

Yesterday, when accelerating from highway paytoll at full speed, i noticed a huge reduction in power. It was as if 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 unclean. I put a piece of tissue over each injector hole, and when i turn the engine on without sparks, the three with gazoline jump right out. The 4th one remains shut. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 I get 0ohm. So i assume the problem is elsewhere.

I also tried to reset the PID without success. The car will start if the G28 is not plugged in and Audi A1 keys is running fine when it is connected but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit is showing 2 bar while the actual pressure is 0.0 when I crank up the engine.

I'm not sure what to do. I feel like i've pretty much all other possibilities out. However, i'm afraid that i might have missed something. Let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump in the g28 can be activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or a parts store. It is simple to test them - simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing up). They should be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines requires to know the position and speed of the crankshaft in order to make a decision about timing of the fuel injector, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these, the diagnostic scanner will show codes that could lead to an engine shut down.

Some of the symptoms of a malfunctioning G28 sensor are an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. If you experience any of these issues, it is most likely that your sensor is deteriorating and needs replacing. They're cheap and easy to find especially when they're an Bosch unit like ours. Alternatively, GM's version of this component is a good option.

5. Tachometer

A failing engine speed sensor could be a cause for numerous issues in your car. It's an essential component of the audi remote key's transmission since it relays information to the ECU about how fast or slow the vehicle's crankshaft is turning. If this sensor fails, it will affect the performance of the transmission, as well as the other car's components.

The G5 engine speed sensor is situated on the outside of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal to control the amount of fuel and boost, and also timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can test the sensor for service failure by checking continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see a resistance of approximately 1000 ohms in these areas. This is a typical part across the audi tt key fob not working 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.