Begin By Meeting Your Fellow Audi G28 Enthusiasts. Steve Jobs Of The Audi G28 Industry How to Replace an Audi G28 Engine Speed Sensor

Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. The sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU via an uncolored wire T55/49, then to the tachometer on the instrument cluster.

1. Engine Speed Sensor


Located on the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via the grey wire. The ECU uses this information to control fuel and boost. It also sends an alert to the G5 Tachometer located in the instrument cluster.

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

If this sensor fails the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync, possibly indicating chain stretch or a jumped link on the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).

Testing can be a bit difficult because there are two pins for the connector and they serve different purposes but the most effective method to test it is to measure the resistance between the sensor and the ECU. When the sensor is functional, it should read approximately 1000 ohms. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.

2. Injectors

Yesterday, as i was accelerating off the highway paytoll at full speed I noticed a massive decrease in power. It was as if the engine was running out of gas. Or, my injectors were not firing. replacement car key audi pull out the spark plugs, 3 were drenched in gazoline, the 4th one was dry. When i crank the engine without sparks i put tissue on top of each injector hole and the 3 that were drenched in gazoline pop out, but the 4th one stays closed. I checked the ground connection of ECU pins 14,30, and 48/55. I got 0ohm. I assume that the problem is elsewhere.

I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it works fine when the G28 connected. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. 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 don't know what to do. I think I've ruled everything else out. I'm afraid i may have missed something. Please let me know If you have any suggestions! TIA!

3. Fuel Pump

The fuel pump on the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is the same as the G4 and both function 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. It is easy to test them - just put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.

4. ECU

The ECU of our 20vt turbo (3B AAN ABY) engines requires to know the position and speed the crankshaft in order to make a decision about timing of the fuel injector, etc. To do this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes badly, you will see codes on the diagnostic scanner that could cause engine shut down.

Some of the symptoms of a malfunctioning G28 sensor are an inaccurate rev counter in the gearbox, gears shifting quicker than normal and/or a misfire when you're in gear. If you are experiencing any of these issues, it is most likely that your sensor is deteriorating and should be replaced. The good news is that they are very cheap and easy to find particularly in the case of a Bosch unit like ours. Alternatively, the GM version of this component is also a good option.

5. Tachometer

A malfunctioning engine sensor can cause a myriad of issues in your car. It's an essential component of the transmission of your Audi since it sends information to the ECU on how fast or slowly the engine of the car is spinning. This sensor could cause the transmission to fail and other car components to be affected.

The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU is then able to process the signal to control the flow of fuel, timig and boost, and also sends it on to the G5 tachometer inside the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms of resistance between these two points. audi a1 key replacement is a standard part that is found across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.