Why Nobody Cares About Audi G28

How to Replace an audi replacement key fob G28 Engine Speed Sensor

In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is located near the transmission's edge just above the flywheel gear. It sends a message to the ECU through an uncolored wire T55/49, then to the tachometer on the instrument cluster.

1. Engine Speed Sensor

It is located on the outside of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 through an uncolored wire. The ECU utilizes this information to control the amount of fuel and boost. It also sends an alert to the G5 Tachometer in instrument cluster.

The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors according to the situation.

If this sensor fails to function, the ECU will display an error code P00160. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumpy chain link in the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).

Testing is a bit tricky because there are two connector pins, and they perform different functions however the best way to test it is by measuring resistance between the sensor and the ECU. When the sensor is fully operational, it should be reading around 1000 ohms. If you're having 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 maximum speed, i noticed a huge decrease in power. It was like the engine was running out of gas. Or, my injectors were not firing. I pulled out the spark plugs this morning, three were soaked with gasoline and the fourth was dry. I put a piece of tissue over each hole in the injector and when I start the engine with no sparks, the three that have gazoline pop right out. The 4th one stays closed. 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 PID without success. The car can start when the G28 is disconnected and runs fine when it is connected however it is experiencing intermittent misfires at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 when i rev the engine.

I'm not sure what to do, as i think i've pretty much ruled out everything else. However, i'm afraid that I may have missed something. Let me know should you have any suggestions! TIA!

3. Fuel Pump

The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is identical to the G4 and both are used in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or from a parts store. It is simple to test them: simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They should be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that needs to know the position and speed of the crankshaft to make decisions about timing of the fuel injectors, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either one of these, the diagnostic scanner will show the codes that could trigger the engine shutting down.

A malfunctioning G28 sensor could cause an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or a misfire in the gear. It is possible that the sensor is failing and needs to be replaced if you experience any of these signs. They are cheap and easy-to-find, especially in the case of an Bosch model like ours. Alternately, GM's version this part is an option.

5. Tachometer

A failing engine speed sensor could be the reason behind a slew of issues in your car. It's a vital component of the audi key fob not working's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is spinning. If this sensor fails, it could affect the performance of the transmission and the other car's components.

The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU uses this signal to control the amount of fuel and boost, as well as timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can test the sensor for any failure by checking 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 [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see approximately 1000 ohms resistance between those points. This is a typical part that is found across the replacement audi key 80 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.