One Of The Most Innovative Things That Are Happening With Audi G28
One Of The Most Innovative Things That Are Happening With Audi G28
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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 near the transmission's edge, above the flywheel gear. It sends a message to the ECU via the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission just above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 via the grey wire. The ECU uses this information to regulate boost and fuel. It also sends an indicator to the G5 Tachometer located in the 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 has reached TDC, and the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails, the ECU will display an error code P00160. This means that the Crank Shaft is not in alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jump in the chain link of the upper chain of timing. The code will not appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit tricky because there are two connector pins, and they serve different purposes however the best way to test it is by measuring resistance between the sensor and the ECU. When the sensor is operational, it should be reading around 1000 ohms. Look for signs of coolant, or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed, i noticed a huge decrease in power. It was as if the engine had run out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, three were drenched in gasoline and the fourth was dry. When i crank the engine, there are no sparks, i place a tissue on the top of each of the injector holes and the 3 drenched with gazoline pop out, but the 4th stays closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I found zero ohm. I think the issue is in another location.
I also tried to reset PID without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However the intermittent misfire issue persists at higher RPM. The coolant sensor (G62), even when unplugged, still shows an ice temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is zero.
I'm not sure what to do. I think I've ruled everything else out. I'm worried that i might have missed something. If anyone has any suggestions, get more info please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and works click here on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or parts store. Test them out by putting your DMM in resistance mode and take measurements between pins 1 (with audi spare key the bump on the connector end up) and 2 (2nd from the 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 new audi key know both the position and speed of the crankshaft to make decisions regarding fuel injector timing, etc. To accomplish this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which could cause engine shut down.
A failing G28 sensor could cause an inaccurate speed counter for the gearbox, a gearbox that shifts faster than normal, and/or an unfire when in the gear. If you have any of these issues, it is likely that your sensor is going bad and should be replaced. The good news is that they are very affordable and easily accessible, especially if you're looking at an Bosch unit like ours. If you prefer, GM's version of this part is an excellent choice.
5. Tachometer
A damaged engine sensor could cause a myriad of issues within your vehicle. It's an essential component of your Audi's transmission, because it communicates to the ECU about how the car's crankshaft is rotating. If the sensor fails, it will disrupt the performance of the transmission as well as the other car's components.
The G5 engine speed sensor is located on the outside of the transmission, above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via an uncolored wire. The ECU uses this signal to regulate the amount of fuel and boost, as well as timig. It also transmits it to the G5 Tachometer in instrument cluster. You can check the sensor for failure by checking 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 detect a resistance of approximately 1000 ohms between these two points. This is a common part that is found across the Audi 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 check here RS2 ADU so good ones might be availble in wrecking yards.