20 Trailblazers Are Leading The Way In Audi G28

How to Replace an Audi Etron Key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is situated 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 in the instrument cluster.

1. Engine Speed Sensor

Located on the edge of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using an uncolored wire. The ECU uses this information to control the amount of fuel and boost. It also sends an indication to the G5 tachometer in the instrument cluster.

The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the location of the camshaft in order to activate the spark and injectors.

If this sensor fails the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain stretching or a jump link on the upper chain of timing. The code won't show without the additional information provided by other sensors (G4 or audi advance key - Https://Portal.uaptc.edu - G40).

It is a little tricky to test as there are several connector pins, and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is in full operation. If you're experiencing issues with this part, check for signs of coolant or oil in the connector bay.

2. Injectors

Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or injectors are not firing any more. In the morning, i removed the spark plugs. Three were drenched in gazoline, the fourth was dry. I placed a tissue over each hole in the injector and when I turn the engine on without sparks, the 3 that have gazoline pop right out. The 4th one stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. I assume that the problem is somewhere else.

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

I'm not certain what to do, i believe that i've ruled out everything else. I'm afraid i may have missed something. If anyone has any ideas please share them! TIA!

3. Fuel Pump

The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate a spare in a wrecking shop or parts store. It is simple to test them: simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump at the connector end facing up). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that has to be aware of the speed and position of the crankshaft in order to make decisions about fuel injector timing etc. In order to do this it uses 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 cause the engine shutting down.

A damaged G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, or a misfire in the gear. If you are experiencing any of these issues it is most likely that your sensor is failing and needs replacing. The good thing is that they are very affordable and readily available, especially when you're looking at an Bosch unit which is what we have. You can also choose the GM version of this unit is also a good option.

5. Tachometer

A failing engine speed sensor could be the cause of a slew of problems in your car. It's a vital component of your audi replacement key service's transmission, because it communicates to the ECU about how the car's crankshaft is spinning. If this sensor fails, it can affect the performance of the transmission as well as the rest of the car's components.

The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It sends signals via a gray wire to the ECU pin T55/49. The ECU then uses and processes the signal to control the flow of fuel, timig and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, Audi Spare Key Replacement you can examine the continuity between pins T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and Audi connect key between pin T6a/1 as well as pin T26a/12. You should observe approximately 1000 ohms resistance between these two points. This is a common part that is found across the audi a1 car key 80 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.