How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. This 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) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU utilizes this information to control boost and fuel. It also sends an indication to the G5 tachometer inside the instrument cluster.
The sensor serves as a reference to correlate with 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 in the right way.
If this sensor fails to function, the ECU will display an error code P00160. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper timing chain. The code won't appear without the additional information provided by other sensors (G4 or G40).
It is a little tricky to test since there are several connector pins, and they all have different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. It should read approximately 1000 ohms when it is operating at its maximum. Examine for signs of coolant, or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant decrease in power. It was as if the engine had run out of gas. Or, my injectors weren't firing. I took out the spark plugs this morning and found that 3 were soaked with gasoline and the 4th was dry. I put tissue over each hole in the injector and when I turn the engine on without sparks, the ones with gazoline jump out. The 4th one remains closed. I inspected the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero Ohm. I think the issue is in another location.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However the intermittent misfire issue persists 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 while the actual pressure is 0.
I'm not sure what to do, as i feel i have pretty much completely ruled out all other possibilities. I'm afraid i may have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent from the RPM sensor. The GM-style transmitter is similar to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily find a spare in a wrecking shop or a parts store. Testing them is easy to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with website the bump on the connector's end 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 are equipped with an ECU that needs to know the speed and position of the crankshaft to make a decision about timing of the fuel injector, for example. It utilizes 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 website show codes that could cause the engine shutting down.
Some of the symptoms of a malfunctioning G28 sensor include an inaccurate gearbox rev counter the gears are shifting faster than normal and/or misfiring when you are in gear. It is website likely that your sensor is failing and requires to be replaced if you experience any of these signs. The good news is they are quite affordable and easily accessible particularly when you're looking at an Bosch sensor, like ours. You can also choose the GM version of this part is also a great option.
5. Tachometer
A faulty engine speed sensor could be the cause of numerous problems in your car. It's a vital more info component of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is turning. When this sensor fails, it can disrupt the performance of the transmission as well as the rest of the car's components.
The G5 engine sensor is located near the edge of the transmission, over get more info the flywheel ring. It transmits signals via gray wire to ECU pin T55/49. The ECU utilizes this signal to regulate the flow of fuel and boost and also to timigrate. It also transmits it to the G5 Tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Also, you can 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 as well as pin T26a/12. It should show around 1000 ohms of resistance between those points. This is a common component across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU, so the best ones might be availble in wrecking yards.