Begin By Meeting With The Steve Jobs Of The Audi G28 Industry

How to Replace an audi keys 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 edge of the transmission, above the flywheel ring gear. It transmits a signal the ECU via a grey wire (T55/49), then to the tachometer in 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 transmits signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.

The sensor is used as a reference for comparing with 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 show a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. However, the code won't appear on its own, without additional information from other sensors (G4 and G40).

It can be a bit difficult to test since there are different pins on the connector and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read approximately 1000 ohms when the sensor is at full operation. If you're having issues with this part, check for evidence of oil or coolant in the connector bay.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, i experienced a big cut in power as if the engine was running out of gas or injectors are not firing at all. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was dry. When I start the engine without 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 stays closed. I checked the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. Therefore, i think the issue is elsewhere.

I also tried to reset the PID without success. The car can start if the G28 is not plugged in 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 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 sure what to do. I believe that I've eliminated everything else. I'm afraid i may have missed something. Please 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 sender is identical to the G4 and both are used in the 80 100, 200, UrS and replacement key for Audi a3; auto-locksmiths77494.bloginder.Com, RS2 cars which is why you can easily locate one at a salvage yard or from a parts store. Test them out - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know the position and speed the crankshaft to determine timing of the fuel injector, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will show codes that could lead to an engine shut down.

The signs of a failing G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal and/or misfiring when you are in gear. It is possible that your sensor is failing and needs to be replaced if you experience any of these symptoms. The good thing is that they are quite affordable and easy to find, especially if you're looking at the Bosch sensor, like ours. Alternatively, the GM version of this unit is also a great option.

5. Tachometer

A faulty engine speed sensor could be the reason behind numerous issues with your car. It's a vital component of the replacement key audi's transmission because it communicates to the ECU about how the car's crankshaft is rotating. When this sensor fails, it could cause problems for the transmission, as well as the other 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 control the amount of fuel and boost, and also timig. It also relays it to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on 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 those two pins. This is a standard part across the audi replacement keys 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.