The No. 1 Question Anyone Working In Audi G28 Must Know How To Answer
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 located on the outside of the transmission just above the flywheel gear. It sends a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission, above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 using an uncolored wire. www.thekeylab.co.uk uses this information to regulate fuel and boost. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used to connect with the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors according to the situation.
If this sensor fails, the ECU will display a P00160 error code. This means that the Crank Shaft is not in line with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jump in the chain link of the upper chain. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
It's a bit tricky to test as there are various connector pins, and each has its own functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. When the sensor is functional, it should read around 1000 ohms. Look for signs of coolant, or oil in the connector bay if you have issues with this component.
2. Injectors
Yesterday accelerating full speed from highway paytoll i had massive power loss as if the engine was running out of gas or the injectors are not firing at all. In the morning, i removed the spark plugs. Three were drenched in gazoline, the fourth one was dry. When I start the engine with no sparks i put tissue on the top of each hole in the injector and the 3 that were drenched in gazoline jump out but the 4th stay shut. I checked the ground connection of ECU pins 14,30, and 48/55. I got zero ohm. I think the issue is elsewhere.
I also tried to reset PID without success. The car will start when the G28 is not plugged in and it runs perfectly when it is plugged in however it has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.
I don't know what to do. I think I've all other possibilities out. But i am afraid I may have missed something. If anyone has any suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump on the g28 is activated by a signal sent by the RPM sensor. The GM-style transmitter is identical to the G4 sender and both work 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 by putting your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector end up) and 2 (2nd from left on the black connector's side). 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 the crankshaft in order to make a decision about fuel injector timing, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these go bad you will get codes on the diagnostic scanner that can lead to engine shutdown.
Some of the symptoms of a failed G28 sensor are an inaccurate rev counter for the gearbox, gears shifting quicker than normal, and/or a misfire when you are in gear. It is probable that the sensor is failing and needs to be replaced if you notice any of these signs. The good news is that they are quite affordable and readily available, especially when you're looking at a Bosch sensor, like ours. You can also choose the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for many problems in your car. It's a crucial component of the transmission in your Audi since it sends information to the ECU regarding how fast or slow the engine of the car is spinning. This sensor could cause the transmission to fail and other car components to be affected.
The G5 engine speed sensor is situated 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 utilizes this signal to control fuel and boost, and also timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. There should be a resistance of approximately 1000 ohms between these points. This part is common across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 DU, so you might find some good ones in wrecking yards.