Why Nobody Cares About Audi G28

How to Replace an audi tt key fob not working G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission, above the flywheel gear. It transmits a signal 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 located on the outside of the transmission, directly above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU utilizes this information to control fuel and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.

The sensor serves as a reference replacement key for audi comparing with the G40 Camshaft Position Sensor. The ecu has to be aware of when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.

If this sensor fails, the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).

It is a little tricky to test since there are different connector pins, and each one has different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is operational, it should be reading around 1000 ohms. If you're experiencing issues with this sensor, look for evidence of coolant or oil in the connector bay.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed, i noticed a huge decrease in power. It was like the engine had run out of gas. Or my injectors weren't firing. This morning i pull out the spark plugs. Three were drenched with gazoline the fourth one was dry. I put tissue over each hole in the injector and when I start the engine without sparks, the 3 with gazoline jump right out. The 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. Therefore, i think the issue is somewhere else.

I also tried to reset the PID but without success. The car is able to start if the G28 is not plugged in and it runs perfectly when it is plugged in however it has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is 0.

I'm not sure what to do, but i feel i have pretty much eliminated everything else. However, i'm afraid that I might have missed something. Let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump of the g28 gets a signal 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 the spare in a salvage shop or parts store. Test them out 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 left on the black connector's side). They must be infinite ohms.

4. ECU

The ECU in our 20vt turbo (3B AAN ABY ADU) engines needs to be aware of the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go badly, you will see codes on the diagnostic scanner which can cause the engine to shut down.

Some of the signs of a failing G28 sensor include an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or a misfire when in gear. It is probable that the sensor is failing and needs to be replaced if you experience any of these signs. The good news is they are very cheap and easily accessible particularly when you're looking at the Bosch sensor, like ours. Alternately, GM's version this part would be an excellent choice.

5. Tachometer

A failing engine sensor could cause a myriad of issues within your vehicle. It's a vital component of the audi spare key cost's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is rotating. This sensor could cause the transmission to fail and other components of the car to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends a signal via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to control fuel and boost, and also timig. It also relays it to the G5 Tachometer in instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see an average resistance of 1000 ohms in these areas. This is a typical component across the audi replacement car keys 80, 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.