How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge, above the flywheel gear. It sends a message to the ECU via an uncolored wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU then uses this information to control the boost, fuel, and timig. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.
If this sensor fails the ECU will display the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain stretching or a jump link on the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test because there are different pins on the connector and each one has different functions. The best way to do it is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is at full operation. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed, i noticed a huge reduction in power. It was like 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 unclean. I placed a tissue over each hole in the injector and when i start the engine without sparks, the three that have gazoline pop right out. The 4th one remains 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 elsewhere.
I also tried to reset the PID without success. The car is able to start when the G28 is not plugged in and is running fine when it is connected but it still is experiencing intermittent misfires at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bar click here when the actual pressure is zero.
I'm not certain what to do, but i feel i have pretty much completely ruled out all other possibilities. I'm worried that i might have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal by the RPM sensor. The GM-style transmitter is the same as the G4 and both function in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a wrecking yard or from a parts store. Testing them is easy by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from the left on the black connector's end). They should 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 to make decisions regarding timing of the fuel injector, for example. In order to do this it uses a Crank here Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner that can cause the engine to shut down.
Some of the symptoms of a failing G28 sensor are an inaccurate rev counter in the gearbox and gears that shift faster than normal and/or misfiring when you're in gear. It is likely that your sensor is failing and requires to be replaced if you encounter any of these signs. The good thing is that they are quite affordable and readily available particularly in the case of the Bosch model, which is what we have. You can click here also choose the GM version of this component is also a good choice.
5. Tachometer
A failing engine speed sensor could be the reason behind many issues in your vehicle. It's a vital component of the Audi's transmission because it communicates to the ECU about how the car's crankshaft is spinning. This sensor can cause the transmission to malfunction and other components in the car to be affected.
The G5 engine speed sensor is located here on the outside of the transmission above the flywheel ring gear and sends a signal directly to the ECU at pin T55/49 through a grey wire. The ECU is then able to process this signal replacement audi car key to regulate fuel, timig and boost as well as transmitting it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. You can also check continuity between pin 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. It should show around 1000 ohms of resistance between these two points. This is a typical part across the Audi 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best parts could be found in wrecking yards.