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 through the grey wire T55/49 and then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, above the flywheel ring. The sensor transmits a signal via the grey wire to pin T55/49. The ECU utilizes this information to regulate the amount of fuel and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu has to know when the crankshaft reached TDC and also the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain is stretched or a jump link on the upper chain of timing. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
It is a little tricky to test since there are various connector pins, and each one has different 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 be reading about 1000 ohms. Examine for signs of coolant or oil in the connector bay if there are issues with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced massive power loss like the engine is out of gas or injectors aren't firing at all. I took out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was dry. I put a piece of tissue over each injector hole, and when i turn the engine on without sparks, the 3 with gazoline jump out. The fourth one remains closed. I tested the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. So i assume the problem is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is not plugged in and it runs perfectly when it is plugged in, but still read more has intermittent misfire issues at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is zero.
I'm not sure what to do, i feel i have pretty much completely get more info ruled out all other possibilities. However, i'm afraid that i might have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal 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. You can easily locate an extra in a wrecking shop or a parts store. It replacement car key audi is easy to test them: simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector's end facing upwards). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that must know the speed and position of the crankshaft in order to make a decision about fuel injector timing etc. To accomplish this, it uses a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a audi spare keys 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 speed counter for the gearbox or a gearbox that shifts more quickly than normal, or a misfire in the gear. If you are experiencing any of these issues, it is likely your sensor is going bad and needs replacing. The good news is that they are very cheap and easily accessible, especially when you're looking at an Bosch sensor, which is what ours are. You can also choose the GM version of this component is also a great option.
5. Tachometer
A failing engine speed sensor could be a cause for many issues in your vehicle. It's an essential component of the Audi's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is rotating. If the sensor fails, it could affect the performance of the transmission as well as the rest of the car's components.
The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear. It transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU then processes this signal to regulate fuel, timig and boost and then sends it on to the G5 tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. Additionally, you read more 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 as well as pin T26a/12. You should see around 1000 ohms of resistance between those points. This is a standard component across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones might be availble in wrecking yards.