25 Unexpected Facts About Audi G28
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches how to replace the G28 Engine Speed Sensor. This sensor is located on the edge of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the outside of the transmission, directly above the flywheel ring. The sensor sends signals through the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu has to be aware of when the crankshaft has reached TDC and also 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 means that the Crank Shaft is not in line with the Intake Camshaft. It could also indicate an issue with the chain or a jumpy chain link in the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).
It is a little tricky to test as there are several pins on the connector, and they all have different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. When the sensor is fully operational, it should read around 1000 ohms. Examine for evidence of coolant or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a significant drop in power. It was like the engine had run out of gas. Or my injectors weren't firing. I pulled out the spark plugs this morning, three were soaked with gasoline and the 4th was dry. I put a piece of tissue over each injector hole, and when i start the engine without sparks, the three with gazoline jump out. The 4th one stays shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. So i assume the problem is in another place.
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 coolant sensor (G62) even if it is not plugged in, shows temperatures of -49c. I also noticed that the oil gauge in the cockpit shows 2 bar while the actual pressure is 0.
I'm not certain what to do, as i believe that i've ruled out everything else. I'm worried that i might have missed something. If anyone has any 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 both operate 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 simple to test them to do - just put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black end of the connector). They should be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY) engines needs to be aware of the position and speed of the crankshaft to make decisions regarding timing of fuel injectors, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these go bad you will get codes on the diagnostic scanner which could cause engine shut down.
A damaged G28 sensor can cause an inaccurate gearbox speed counter or a gearbox that shifts more quickly than normal, or an unfire when in gear. webpage is likely that the sensor is failing and requires to be replaced if you encounter any of these symptoms. They're inexpensive and easy to locate especially in the case of an Bosch unit like ours. Alternatively, the GM version of this component is also a great option.
5. Tachometer
A failing engine speed sensor could be the reason behind numerous problems in your car. It is a crucial part of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is turning. This sensor can cause the transmission to malfunction and other components of the car to be affected.
The G5 engine sensor is located near the edge of the transmission, over the flywheel ring. It sends a signal via a gray wire to the ECU pin T55/49. The ECU is then able to process the signal to control fuel, timig and boost as well as sends it on to the G5 Tachometer located in the instrument cluster. You can check for sensor failure by examining the continuity from the sensor to the tachometer. Additionally, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 as well as pin T26a/12. It should show approximately 1000 ohms of resistance between those points. This is a standard component across the Audi 80 100 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.