"The Ultimate Cheat Sheet On Audi G28
How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows you how to replace the G28 Engine Speed Sensor. The sensor is located near the transmission's edge, above the flywheel gear. It sends a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, just above the flywheel ring. The sensor sends an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control fuel, timig and boost. It also sends an indicator to the G5 Tachometer in instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and the location of the camshaft so it can activate spark and injectors accordingly.
If this sensor fails the ECU will display an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync and could indicate chain stretch or a jumped link on the upper timing chain. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult because there are two connector pins, and they have different functions however the best method of testing it is by measuring resistance between the sensor and the ECU. It should read about 1000 ohms when the sensor is in full operation. If you're having issues with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll i had a big cut in power as if the engine was running out of gas or the injectors aren't firing at all. replacement key audi The Key Lab pulled out the spark plugs this morning and found that 3 were soaked in gasoline, and the 4th was dry. When I start the engine with no sparks, I put a piece of tissue on the top of each hole in the injector, the 3 drenched with gazoline leap out, however the 4th stay closed. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 i get zero ohm. Therefore, i think the issue is somewhere else.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 connected. However, the intermittent misfire problem continues to occur 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 bar but the actual pressure is zero.
I'm not sure what to do. I think I've eliminated everything else. I'm worried that i might have missed something. Please let me know if you have any ideas! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is the same as the G4 and both function in the 80 100, 200, UrS and RS2 cars so you can easily find one at a junkyard or in a local parts store. Test them out to do - just put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's side). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the speed and position of the crankshaft in order to make a decision about timing of the fuel injector, for example. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these go bad you will get codes on the diagnostic scanner which could cause engine shut down.
Some of the signs of a failed G28 sensor are an inaccurate gearbox rev counter, gears shifting quicker than normal, and/or a misfire when in gear. It is possible that your sensor is failing and needs to be replaced if you notice any of these signs. The good thing is that they are quite affordable and easily accessible, especially when you're looking at an Bosch sensor, which is what we have. Alternately, the GM version of this component is also a great option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for a slew of issues with your car. It is an important part of the transmission of your Audi, as it transmits information to the ECU about how fast or slowly the engine is spinning. This sensor can cause the transmission to malfunction and other components in the car to be affected.
The G5 engine speed sensor is located at the edge of the transmission above the flywheel ring gear and sends a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to control fuel and boost, and also to timigrate. It also transmits 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]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should observe approximately 1000 ohms resistance between these two points. This part is common across the Audi 80-100-200-RS2 range, from the 1985 MC up to the 1997 UrS AN and 1995 RS2 Du, so you might find some good ones in wrecking yards.