20 Myths About Audi G28: Dispelled
20 Myths About Audi G28: Dispelled
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via an uncolored wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, just above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indicator to the G5 Tachometer within the instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors accordingly.
If this sensor fails when it 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 be a sign of a chain stretch or a jumpy chain link in the upper timing chain. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
It is a little tricky to test as there are several pins on the connector, and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read about 1000 ohms when the sensor is operating at its maximum. Examine for signs of coolant or oil in the connector bay if you are experiencing issues with this component.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a significant reduction in power. It was like the engine had run out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs, three were soaked with gazoline and the fourth was dry. When I crank the engine, there are no sparks, i place a tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stays shut. I tested the ground connection on ECU pins check here 14/55, 30/55 and 48/55. I get 0ohm. I think the issue is somewhere else.
I also tried to reset the PID without success. The car will start when the G28 is unplugged, and it runs fine with the G28 connected. However the intermittent misfire issue persists at higher RPM. The temperature sensor for coolant read more (G62) shows the wrong temp value that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is zero.
I'm not here 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. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from the RPM sensor. The GM-style sender is identical to the G4 and both function in the 80 100, 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or in a local parts store. It is easy 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 end facing up). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines needs to know the position and speed of the crankshaft to make decisions regarding fuel injector timing, etc. In order to do this it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these, the diagnostic scanner will display codes that could cause an engine shut down.
A failing G28 sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts more quickly than normal, and/or a misfire while in the gear. If you have any of these issues, it is most likely that your sensor is failing and requires replacement. The good news is they are very cheap and easily accessible particularly when you're looking at a Bosch sensor, which is what ours are. If you prefer, GM's version of this part would be a good option.
5. Tachometer
A malfunctioning engine speed sensor could be the reason behind numerous problems in check here your car. It's a vital component of the Audi's transmission since it relays information to the ECU about how the car's crankshaft is turning. This sensor can cause the transmission to malfunction and other car components to be affected.
The G5 engine speed sensor is situated on the edge of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal 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 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 click here should detect a resistance of approximately 1000 ohms between these two points. This is a typical part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.