How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. This sensor is located on the edge of the transmission just above the flywheel ring gear. It transmits a signal the ECU via the grey wire (T55/49), then to the tachometer located in 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 boost and fuel. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu must know when the crankshaft reached TDC, and the position of the camshaft, so that it can activate the spark and injectors.
If this sensor fails, the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are not in sync and could indicate the chain stretching or a jump link on the upper chain of timing. The code won't show without the additional information supplied by other sensors (G4 or G40).
It's a bit tricky to test since there are different pins on the connector, and each one has different functions. The best method for doing this is to measure the resistance between the ECU and the sensor. It should read approximately 1000 ohms if the sensor is operating at its maximum. Look for signs of coolant, or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, i experienced massive power loss like the engine is out of gas or injectors are not firing at all. This morning i pull out the spark plugs, three were drenched in gazoline, the 4th one was dry. I placed a tissue over each injector hole, and when i start the engine without sparks, the 3 with gazoline jump right out. The 4th one remains shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I get zero Ohm. So i assume the problem is elsewhere.
I also tried to reset PID without success. The car can get more info start when the G28 is disconnected and it runs perfectly when it is connected however it has the intermittent more info misfire issue at higher RPM. The coolant sensor (G62) even when unplugged, still shows an ice temperature of -49c. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I'm not certain what to do, i think i've pretty much completely ruled out all other possibilities. I'm worried that i might have missed something. If anyone has suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is similar to the G4 sender and works on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or parts store. It is simple to test them to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black connector's side). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to be aware of the position and speed the crankshaft to determine timing of the fuel injector, etc. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you encounter a problem with either of these, the diagnostic scanner will display the codes that could trigger an engine shutdown.
A damaged G28 sensor can cause an inaccurate gearbox speed counter or a gearbox that shifts more quickly than normal, or a misfire in the gear. It is probable that the sensor is failing and requires to be replaced if you notice any of these symptoms. The good news is that they are quite affordable and easily accessible, especially if you're looking at a Bosch model, like ours. Alternatively, GM's version of this part is an option.
5. Tachometer
A malfunctioning engine speed sensor could be the cause of many issues in your car. It is a crucial part of the Audi's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is more info turning. This sensor can cause the transmission to fail and other components in the car to be affected.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It sends an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU then processes this signal to control fuel, timig and boost, and also sends it on to the G5 Tachometer located in click here the instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms of resistance between these two points. This is the same across the Audi 80-100-200-RS2 range, beginning with the 1985 MC audi key replacement and up to the 1997 UrS An and 1995 RS2 Du, so you might find some good ones in wrecking yards.