The Most Profound Problems In Audi G28
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 near the edges of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using the grey wire. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends signals to the G5 tachometer inside the instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu needs to 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 to function, 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 be a sign of the possibility of a chain stretch or jumped chain link in the upper chain of timing. audi q7 car key replacement will not appear without the additional information supplied by other sensors (G4 or G40).
It is a little tricky to test since there are various pins on the connector and each has its own functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. If the sensor is operational, it should read about 1000 ohms. Examine for signs of coolant or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced a big cut in power as if the engine was running out of gas or the injectors aren't firing any more. I pulled out the spark plugs this morning, 3 were drenched in gasoline and the fourth was unclean. When I crank the engine with no sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline pop out, but the 4th stay closed. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero ohm. I think the issue is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However, the intermittent misfire problem continues to occur at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of that is -49c even after unplugging it. 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 believe that I've all other possibilities out. However, i'm afraid that I might have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style sensor is identical to the G4 and they both work in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a wrecking yard or at a parts store. Test them out to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that has to know the speed and position of the crankshaft in order to make decisions about timing of the fuel injector, for example. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either of these sensors, the diagnostic scanner will display codes that could cause an engine shutdown.
A damaged G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster 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 deteriorating and requires replacement. They are cheap and easy-to-find especially if they're a Bosch sensor like ours. You can also choose the GM version of this component is also a good choice.
5. Tachometer
A failing engine sensor could cause a myriad of issues within your vehicle. It is an important part of the transmission of your Audi since it sends information to the ECU about how fast or slowly the engine is spinning. If the sensor fails, it will disrupt the performance of the transmission and the other car's components.
The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49, via an uncolored wire. The ECU then uses and processes this signal to control the flow of fuel, timig and boost, and also transmitting it to the G5 tachometer in the instrument cluster. You can determine if the sensor is in failure by checking continuity from 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 [79]) and between pin T6a/1 and pin T26a/12. There should be the resistance to be around 1000 ohms between these points. This is the same across the Audi 80-100-200-RS2 model, ranging from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU, so you might find good ones in wrecking yards.