Why Nobody Cares About Audi G28

How to Replace an Audi 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 just above the flywheel ring gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer in the instrument cluster.

1. Engine Speed Sensor

The grey wire is located at the edges of the transmission, above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends an indication to the G5 tachometer inside the instrument cluster.

The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC, and where the camshaft lies so that it can activate the spark and injectors.

If this sensor fails, the ECU will display an error code P00160. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also indicate an issue with the chain or a jump in the chain link of the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).

It's a bit tricky to test as there are various connector pins, and they all have 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 approximately 1000 ohms. Examine for signs of coolant or oil in the connector bay if there are issues with this part.

2. Injectors

Yesterday, when i was accelerating to the fullest speed from highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or injectors are not firing at all. Today, i pulled out the spark plugs. Three were soaked with gazoline and the fourth one was dry. I placed a tissue over each injector hole, and when i turn the engine on without sparks, the ones with gazoline jump out. The 4th one remains closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. I assume that the problem is elsewhere.

I also tried to reset the PID without success. The car will start if the G28 is disconnected and runs fine when it is connected however it is experiencing intermittent misfires at higher RPM. The temperature sensor replacement key for audi a4 the coolant (G62) shows the wrong temperature value of that is -49c even after unplugging it. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar while the actual pressure is 0.0 if i crank up the engine.

I'm not sure what to do. I believe that I've eliminated everything else. But i'm worried that i might have missed something. If anyone has suggestions, please let me know! 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 the same as the G4 and they both work in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or at a parts store. Testing them is easy to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black end of the connector). They must be infinite ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines must know both the position and speed of the crankshaft 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 either of these go badly, you will see codes on the diagnostic scanner that could cause engine shut down.

The signs of a failing G28 sensor include an inaccurate rev counter in the gearbox and gears that shift faster than normal, and/or a misfire when you're in gear. It is likely that your sensor is failing and needs to be replaced if you encounter any of these symptoms. They are cheap and easy-to-find especially when they're an Bosch unit like ours. Alternately, the GM version of this component is also a good option.

5. Tachometer

A faulty engine speed sensor could be the cause of a slew of issues in your car. It's an essential component of your audi replacement keys's transmission, since it relays information to the ECU about how fast or slow the car's crankshaft is rotating. When this sensor fails, it will cause problems key for audi 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 a signal via gray wire to ECU pin T55/49. The ECU then uses and processes the signal to control fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms of resistance between these two points. This is a common feature across the audi replacement car keys 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 Du So, you may find good ones in wrecking yards.