How to Replace audi car key replacement shows how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge just above the flywheel gear. It transmits a signal the ECU via a grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
Located on the edge of the transmission, above the flywheel ring gear, the G28 Engine Speed Sensor sends signals to ECU pin T55/49 using a grey wire. The ECU utilizes this information to control boost and fuel. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used to correlate with the G40 Camshaft position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors according to the situation.
If this sensor fails, the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper chain of timing. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit tricky since 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. It should read approximately 1000 ohms if the sensor is operating at its maximum. If you're experiencing issues with this component, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, as i was accelerating off 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 weren't firing. In the morning, i removed the spark plugs, 3 were soaked with gazoline and the 4th one was dry. When I start the engine without sparks, i place a tissue on the top of each hole in the injector and the 3 that were drenched in gazoline leap out, however the 4th stays closed. I tried to test the ground connections of ECU pins 14,30, and 48/55. I got 0ohm. I'm assuming that the issue is in another location.
I also tried to reset the PID without success. The car is able to start if the G28 is not plugged in and it runs perfectly when it is connected but it still is experiencing intermittent misfires at higher RPM. The temperature sensor for the 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 when the actual pressure is zero.
I'm not sure what to do, but i think i've pretty much ruled out everything else. I'm afraid i may have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the RPM sensor. The GM-style sender is the same as the G4 and both function in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a salvage yard or from a parts store. It is easy to test them - simply switch your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that has to know the speed and position of the crankshaft in order to make a decision about timing of the fuel injectors, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you encounter a problem with either of these, the diagnostic scanner will display the codes that could trigger the engine shutting down.
A malfunctioning G28 sensor could result in an inaccurate speed counter for your gearbox and a gearbox which shifts faster than normal, and/or a misfire while in the gear. It is likely that the 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 easily accessible, especially if you're looking at a Bosch sensor, like ours. Alternatively, the GM version of this component is also a great option.
5. Tachometer
A damaged engine sensor could cause a number of problems within your vehicle. It's a vital component of the Audi's transmission because it communicates to the ECU about how fast or slow the car's crankshaft is rotating. If the sensor fails, it will affect the performance of the transmission and the other car's components.
The G5 engine sensor is located at the edge of the transmission, over the flywheel ring. It sends an electrical signal through a gray wire to the ECU pin T55/49. The ECU then processes the signal to control fuel, timig and boost as well as sends it on to the G5 tachometer in the instrument cluster. You can check the sensor for failure by examining the 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 see a resistance of approximately 1000 ohms between these points. This is a standard part that is found 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.