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 situated on the edge of the transmission above the flywheel ring gear. It transmits a signal the ECU via an uncolored wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via an uncolored wire. The ECU then uses this information to control the boost, fuel, and timig. car key replacement audi sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. how much is an audi key replacement must be aware when the crankshaft is TDC and where the camshaft is so it can start 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 could indicate the chain stretching or a jump link on the upper chain of timing. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky because there are two pins for the connector and they have different functions but the best way to test it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms when it is in full operation. If you are having problems with this part, check for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a massive drop in power. It was like the engine had run out of gas. Or, my injectors were not firing. Today, i pulled out the spark plugs, 3 were soaked with gazoline and the 4th one was dry. When i crank the engine with no sparks i put tissue on the top of each hole in the injector, the 3 drenched with gazoline pop out, but the 4th one stays closed. I checked the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ i get zero Ohm. So i assume the problem is in another place.
I also tried to reset PID but without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However the intermittent misfire issue persists 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 bars when the actual pressure is 0.
I'm not certain what to do, but i feel i have pretty much completely ruled out all other possibilities. However, i'm afraid that I may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to 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 take measurements between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know both the speed and position of the crankshaft to determine timing of the fuel injector, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these, the diagnostic scanner will display the codes that could trigger an engine shutdown.
The signs of a failed G28 sensor include an inaccurate gearbox rev counter, gears shifting quicker than normal and/or a misfire when you are in gear. It is probable that your sensor is failing and requires to be replaced if you experience any of these symptoms. The good news is that they are very cheap and easily accessible, especially when you're looking at an Bosch sensor, which is what we have. If you prefer, GM's version of this part would be an excellent choice.
5. Tachometer
A failing engine speed sensor could be the cause of numerous issues in your vehicle. It is an important part of the transmission in your Audi because it relays information to the ECU regarding how fast or slow the engine of the car is spinning. This sensor could cause the transmission to malfunction and other components of the car to be affected.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends signals via an uncolored wire to the ECU pin T55/49. The ECU is then able to process this signal to control fuel, timig and boost, and also transmitting it to the G5 tachometer inside the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. There should be a resistance of approximately 1000 ohms between these points. This is a typical 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. Good parts could be found in wrecking yards.