Why People Don't Care About Audi G28
Why People Don't Care About Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
In this video Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. This sensor is situated at the edge of transmission, above the flywheel gear. It transmits a signal the ECU via an uncolored wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU uses this information to control boost and fuel. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used as a reference point to connect 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 trigger spark and injectors in the right way.
If this sensor fails, the ECU will display a P00160 error message. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).
It is a little tricky to test because there are different pins on the connector and each has its own functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read approximately 1000 ohms when it is in full operation. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a significant drop in power. It was like the engine was running out of gas. Or, my injectors weren't firing. Today, i pulled out the spark plugs. Three were drenched with gazoline the fourth was dry. I put a piece of tissue over each hole in the injector and when i start the engine with no sparks, the 3 that have gazoline pop right out. The 4th one remains closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I got zero ohm. So i assume the problem is elsewhere.
I also tried to reset the PID but with no luck. The car will start when the G28 is unplugged, and it is running fine with the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The coolant sensor (G62), even when unplugged, still shows temperatures of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, i believe that i've eliminated everything else. I'm afraid i may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style transmitter is similar to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find a spare in a wrecking shop or parts store. Test them out - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know both the speed and position of the crankshaft to make decisions regarding fuel injector timing, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these goes bad you will get codes on the diagnostic scanner that can cause the engine to shut down.
A failing G28 click here sensor could result in an inaccurate gearbox speed counter or a gearbox that shifts faster than normal, and/or a misfire while in gear. It is probable that the sensor is failing and requires to be replaced if you encounter any of these signs. They're inexpensive and easy to locate especially in the case of a Bosch sensor like ours. Alternately, the GM version of this part is also a good choice.
5. Tachometer
A faulty engine speed sensor could be the reason behind a slew of issues in your car. It is an important part of the transmission in your Audi because it relays information to the ECU on how fast or slowly the car's engine is turning. If this sensor fails, it could cause more info problems for the transmission as well as the rest of the car's components.
The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It sends an electrical here signal through a gray wire to the ECU pin T55/49. The ECU then processes the signal to control fuel, timig, read more and boost and then sends it on to the G5 tachometer in the instrument cluster. You can check for sensor failure by examining the continuity of the sensor to the tachometer. Additionally, you can examine the continuity between pins 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. There should be the resistance to be around 1000 ohms between these points. This part is common across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS An and 1995 RS2 DU, so you might find good ones in more info wrecking yards.