This Is The Ultimate Cheat Sheet On Audi G28
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician teaches you how to replace the G28 Engine Speed Sensor. The sensor is located on the edge of the transmission just above the flywheel ring gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, just above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to control fuel and boost. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors according to the situation.
If this sensor fails to function, the ECU will display a P00160 error message. This indicates that the Crank Shaft is out of line with the Intake Camshaft. It could also indicate an issue with the chain or a jumped chain link in the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
It's a bit tricky to test because there are different pins on the connector, and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms if the sensor is at full operation. Check for signs of coolant, or oil in the connector bay if you are experiencing issues with this component.
2. audi a3 key replacement , while accelerating at full speed from the highway paytoll, I experienced a big cut in power as if the engine was running out of gas or the injectors are not firing at all. I took out the spark plugs this morning, three were drenched in gasoline and the 4th was dry. I put tissue over each injector hole, and when i start the engine with no sparks, the 3 with gazoline jump right out. The 4th one stays shut. I tested the ground connection on ECU pins 14/55, 30/55 and 48/55. I got 0ohm. I think the issue is somewhere else.
I also tried to reset the PID with no success. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However, the intermittent misfire problem persists at higher RPM. The temperature sensor for 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 while the actual pressure is zero.
I don't know what to do. I believe that I've ruled everything else out. But i am afraid i might have missed something. Please let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal by 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 parts store. Testing them is easy - put your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's end). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines must know the position and speed the crankshaft in order to make a decision about fuel injector timing, etc. To accomplish this, it utilizes 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 that could cause engine shut down.
A malfunctioning G28 sensor could result in an inaccurate speed counter for your gearbox or a gearbox that shifts faster than normal, or a misfire while in gear. It is likely that your sensor is failing and requires to be replaced if you encounter any of these symptoms. The good news is they are very affordable and readily available particularly in the case of the Bosch model, which is what we have. You can also choose the GM version of this part is also a good choice.
5. Tachometer
A faulty engine speed sensor could be the reason behind numerous problems in your car. It is a crucial part of the Audi's transmission since it relays information to the ECU about how fast or slow the vehicle's crankshaft is turning. If this sensor fails, it could affect the performance of the transmission and the other car's components.
The G5 engine speed sensor is located on the edge of the transmission, above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 via an uncolored wire. The ECU is then able to process this signal to control fuel, timig and boost and then sends it on to the G5 tachometer in 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. There should be a resistance of approximately 1000 ohms between these points. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC up to the 1997 UrS AN and 1995 RS2 DU, so you might find good ones in wrecking yards.