This Is The Ultimate Cheat Sheet On Audi G28
This Is The Ultimate Cheat Sheet On Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you 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 transmits a signal the ECU via the grey wire (T55/49), then to the tachometer within 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 signals through the grey wire to pin T55/49. The ECU utilizes this information to control the amount of fuel and boost. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor serves as a reference for comparing 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 trigger spark and injectors accordingly.
If this sensor fails, the ECU will throw a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched or a jump link on the upper timing chain. However, the code won't be displayed on its own without additional information from other sensors (G4 and G40).
It is a little tricky to test as there are different pins on the connector, and each one has different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is functional, it should read approximately 1000 ohms. Examine for signs of coolant, or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, I experienced an abrupt drop in power like the engine is running out of gas or injectors are not firing anymore. I pulled out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. When I start the engine with no sparks i put tissue on the top of each hole in the injector and the 3 drenched with gazoline pop out, but 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 in another place.
I also tried to reset PID without success. The car will start when the G28 is not plugged in and it runs perfectly when more info it is plugged in, but still has the intermittent misfire issue at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. Also i noticed that the oil pressure gauge in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 when i rev the engine.
I don't know what to do. I feel like i've pretty much eliminated everything else. I'm afraid i replacement audi key may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. It is simple to test them by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines requires to be aware of the speed and position of the crankshaft to make decisions regarding timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either of these, the diagnostic scanner will show codes that could lead to an engine shut down.
Some of the signs of a failed G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal and/or misfiring when in gear. If you experience any of these issues it is most likely that your sensor is failing and requires replacement. The good news is they are very affordable and easily accessible, especially in the case of the Bosch sensor, which is what we have. You can also choose the GM version of this unit is also a great option.
5. Tachometer
A failing engine speed sensor could be a cause for numerous issues with your car. It is a crucial part of the Audi's transmission since it relays information to the ECU about how fast or slow the car's crankshaft is turning. If this sensor fails, it will disrupt the performance of the transmission, as well as the rest of the car's components.
The G5 engine speed sensor is located at the edge of the transmission above the flywheel ring gear. It sends a signal directly to the ECU at pin T55/49 via a grey wire. The ECU then uses and processes this signal to regulate the flow of fuel, timig and boost as well click here as transmitting it to the G5 tachometer inside the instrument cluster. You can test the sensor for failure by examining 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 [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between these two points. This check here is a read more common part across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.