20 Myths About Audi G28: Dispelled

How to Replace an audi key G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is situated on the outside of the transmission over the flywheel gear. It transmits a signal the ECU via a grey wire (T55/49), then to the tachometer located in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, above the flywheel ring. This sensor sends 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 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 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 to function, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).

Testing is a bit challenging as there are two different connector pins, and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading around 1000 ohms. Examine for signs of coolant or oil in the connector bay if you are experiencing problems with this part.

2. Injectors

Yesterday accelerating full speed from highway paytoll i had massive power loss like the engine is out of gas or the injectors are not firing at all. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the 4th was dry. I put tissue over each hole in the injector and when i start the engine without sparks, the ones with gazoline jump right out. The 4th one remains shut. I tested the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got zero Ohm. I think the issue is in another location.

I also tried to reset the PID with no success. The car key cover audi will start if the G28 is not plugged in and runs fine when it is connected, but still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. Also, i noticed that the oil pressure gauge in the cockpit shows 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. I'm concerned that i may have missed something. Please let me know if you have any ideas! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find the spare in a salvage shop or parts store. It is simple to test them - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that needs to know the position and speed of the crankshaft in order to make decisions regarding fuel injector timing etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either of these, the diagnostic scanner will display codes that could cause the engine shutting down.

A damaged G28 sensor could cause an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, and/or an unfire when in the gear. If you experience any of these problems, it is most likely that your sensor is failing and requires replacement audi a3 key. The good news is they are very cheap and easy to find, especially when you're looking at a Bosch unit which is what ours are. Alternatively, GM's version of this component is a good option.

5. Tachometer

A malfunctioning engine sensor can cause a number of problems in your vehicle. It is an important part of the transmission of your audi smart key replacement, as it transmits information to the ECU on how fast or slowly the car's engine is turning. If the sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.

The G5 engine speed sensor is located at the outside of the transmission, 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 fuel and boost, as well as timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can check for sensor failure by checking continuity from the sensor to the tachometer. Also, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]) and between pin T6a/1 and pin T26a/12. You should see the resistance to be around 1000 ohms in these areas. This is a standard component across the audi key fobs 80 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.