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 over the flywheel gear. It transmits a signal to the ECU via an uncolored wire (T55/49) and then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, just above the flywheel ring. The sensor sends a signal via the grey wire to pin T55/49. The ECU utilizes this information to regulate fuel and boost. It also sends an indicator to the G5 Tachometer within the 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 location of the camshaft in order to activate the spark and injectors.
If this sensor fails when it fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate a chain stretch or a jumped chain link in the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
It can be a bit difficult to test as there are different pins on the connector, and each has its own functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is at full operation. Check for signs of coolant or oil in the connector bay if there are problems with this part.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or the injectors aren't firing anymore. I took out the spark plugs this morning, 3 were soaked with gasoline and the fourth was dry. When i crank the engine, there are no sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline pop out, but the 4th stay closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. i get zero ohm. I think the issue is somewhere else.
I also tried to reset PID but without success. The car will start when the G28 is unplugged, and it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The coolant temperature sensor (G62) shows the wrong temperature value of that is -49c even after unplugging it. I also noticed that the gauge for oil pressure in the cockpit shows 2 bar when the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do, but i think i've pretty much completely ruled out all other possibilities. But i'm worried that I may have missed something. Let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. read more The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. You can easily find an extra in a wrecking shop or a parts store. It is easy to test them - simply switch your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing up). They must be infinite Ohms.
4. ECU
Our 20vt more info turbo (3B, AAN, ABY and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, for example. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go badly, you will see codes on the diagnostic scanner audi tt keys that can lead to engine shutdown.
A malfunctioning G28 sensor could result in an inaccurate gearbox click here speed counter or a gearbox that shifts faster than normal, or a misfire in gear. It is possible that your sensor is failing and needs to be replaced if you encounter any of these symptoms. They're cheap and easy to find especially when they're an Bosch unit like ours. Alternately, GM's version this part would be an option.
5. Tachometer
A damaged engine sensor could cause a myriad of issues in your car. It is here a crucial part of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is rotating. When this sensor fails, it can affect the performance of the transmission and the other car's components.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the amount of fuel and boost, as well as timig. It also sends 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 [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see a resistance of approximately 1000 ohms between these two points. This is a common 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 good ones could be available in wrecking yards.