4 Dirty Little Secrets About The Audi G28 Industry

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 on the instrument cluster.

1. Engine Speed Sensor

The grey wire is located on the outside of the transmission, just above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends signals to the G5 Tachometer located in the instrument cluster.

The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know 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 when it fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate an issue with the chain or a jumpy chain link in the upper chain of timing. The code won't appear without the additional information provided by other sensors (G4 or G40).

Testing is a bit challenging as there are two different connector pins, and they have different functions but the best method to test it is to measure resistance between the sensor and the ECU. It should read about 1000 ohms if the sensor is operating at its maximum. Look for evidence of coolant or oil in the connector bay if you have problems with this part.

2. Injectors

Yesterday, while accelerating at full speed from the highway paytoll, I experienced an abrupt drop in power like the engine is out of gas or injectors aren't firing at all. This morning i pull out the spark plugs, three were soaked with gazoline and the 4th one was dry. When i crank the engine, there are no sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th one stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I found 0ohm. So i assume the problem is elsewhere.

I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it is running fine with the G28 connected. However the intermittent misfire issue continues to occur at higher RPM. The coolant temperature sensor (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar when the actual pressure is 0.

I'm not certain what to do, as i think i've pretty much ruled out everything else. But i'm worried that i might have missed something. If anyone has any ideas please let me know! TIA!

3. Fuel Pump

The fuel pump in the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or parts store. It is simple to test them - just switch your DMM into resistance mode and test the distance between website pins 1 and 2 (with the bump at the connector's end facing up). They must be infinite Ohms.

4. ECU

Our 20vt turbo (3B AAN, ABY, and ADU) engines are equipped with an ECU that must know the speed and position of the crankshaft to make a decision about timing of the fuel injector, for example. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these, the diagnostic scanner will show codes that could cause an engine shutdown.

The signs of a failed G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or a misfire when you are in gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these signs. They're inexpensive and easy to locate especially in the case of an Bosch unit like ours. Alternately, the GM version of this unit is also a good choice.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues in your vehicle. It's a crucial component of the transmission of your Audi since it sends information to the ECU about how fast or slow the engine of the car is spinning. If this sensor click here fails, it could disrupt the performance of the transmission and the rest of the car's components.

The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through an uncolored wire. The ECU utilizes this signal more info to control fuel and boost, and also timig. It also sends it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by examining the continuity of the sensor to the here tachometer. Additionally, 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 an average resistance of more info 1000 ohms between these points. This is a standard component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.