What NOT To Do With The Audi G28 Industry
What NOT To Do With The Audi G28 Industry
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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 near the transmission's edge just above the flywheel gear. It transmits a signal to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, directly above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to regulate fuel and boost. It also sends an indication to the G5 tachometer in the instrument cluster.
The sensor is used as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must be aware of when the crankshaft has reached TDC, and the location of the camshaft so that it can activate the spark and injectors.
If this sensor fails to function, the ECU will display an error code P00160. This means that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of an issue with the chain or a jumpy chain link in the upper timing chain. However the code will not be displayed on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky as there are two different connector pins and they perform different functions but the most effective way to test it is by measuring resistance between the sensor and the ECU. When the sensor is fully functional, it should read approximately 1000 ohms. If you're having issues with this component, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at a high speed I noticed a significant decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, three were soaked in gasoline, and the fourth was dry. When I crank the engine with no sparks i put tissue on top of each injector hole and the 3 drenched with gazoline pop out, but the 4th stay shut. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. I got 0ohm. I assume that the problem is somewhere else.
I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it runs fine with the G28 connected. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62), even when it is unplugged, shows temperatures of what is the audi advanced key -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 sure what to click here do, but i think i've pretty much completely ruled out all other possibilities. However, i'm afraid that I might have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 gets a signal from 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. You can easily locate an extra in a wrecking shop or parts store. Test them out 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 audi tt keys (2nd from left on the black end of the connector). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know the speed and position of the crankshaft to determine timing of fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If either of these goes badly, you will see codes on the diagnostic scanner that can cause the engine to shut down.
A damaged G28 sensor could result in an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, or a misfire in gear. It is here probable that your sensor is failing and needs to be replaced if you notice any of these signs. They are cheap and easy-to-find, especially if they're a Bosch unit like ours. Alternatively, GM's version of this part would be a good option.
5. Tachometer
A failing engine speed sensor could be the cause of a slew of issues in your car. It's an essential component of the transmission in your Audi, as it transmits information to the ECU regarding how fast or slow the engine is spinning. This sensor can cause the transmission to fail and other components of the car to be affected.
The G5 engine sensor is located at the outskirts of the transmission, just above the flywheel ring. It transmits an electrical signal through a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control the flow of fuel and boost and also to timigrate. It also relays it to the G5 Tachometer inside the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. You can also 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. You should see approximately 1000 ohms of resistance between those points. This is a common part that is found across the Audi 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 here RS2 ADU. Good ones might be availble in wrecking yards.