25 Shocking Facts About Audi G28
25 Shocking Facts About Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. This sensor is situated near the transmission's edge, above the flywheel gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer 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 an electrical signal to ECU pin T55/49 via the grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors according to the situation.
If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. However the code will not appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky because there are two connector pins, and they serve different purposes however the best method of testing it is to measure resistance between the sensor and the ECU. When the sensor is operational, it should be reading around 1000 ohms. Check for evidence of coolant or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll i had an abrupt drop in power as if the engine was running out of gas or the injectors are not firing anymore. I took out the spark plugs this morning, three were drenched in gasoline and the fourth was unclean. When I start the engine with no sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. I think the issue is elsewhere.
I also tried to reset 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 still has the intermittent misfire issue at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is zero.
I'm not sure what to do, as i believe that i've eliminated everything else. But i'm worried that I may have missed something. If anyone has suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent from the RPM sensor. The GM-style sender 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. It is easy to test them: simply put your DMM into resistance mode and audi replacement key test the distance between pins 1 and 2 (with the bump at the connector's end read more facing upwards). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that has to be aware of the speed and position of the crankshaft to make a decision about fuel injector timing etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either of these, the diagnostic scanner will display the codes that could trigger an engine shut down.
Some of the symptoms of a failing G28 sensor are an inaccurate gearbox rev counter, gears shifting quicker than normal and/or a misfire when in gear. It is probable that your sensor is failing and needs to be replaced if you encounter any of audi lost key replacement these symptoms. The good news is they are very affordable and readily available, especially if you're looking at the Bosch sensor, which is what ours are. Alternately, GM's version this part would be an excellent choice.
5. Tachometer
A failing engine sensor could cause a variety of issues in your vehicle. It's a vital component of the Audi's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is rotating. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine speed sensor is located at the outside of the transmission above the flywheel ring gear audi tt keys and transmits a signal to the ECU at pin T55/49, via an uncolored wire. The ECU then processes this signal to control fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can test the sensor for failure by checking continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see approximately 1000 audi a4 key replacement ohms of resistance between these two points. This is a standard part that is found across the Audi 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.