5 Laws Everyone Working In Audi G28 Should Be Aware Of
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 situated at the top 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 in 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 a signal to ECU pin T55/49 using a grey wire. The ECU utilizes this information to control fuel and boost. audi a1 key sends signals to the G5 tachometer in the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must be aware when the crankshaft is TDC and where the camshaft is so it can activate spark and injectors according to the situation.
If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync, possibly indicating the chain stretching or a jump link on the upper timing chain. However, the code won't appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit challenging since there are two connector pins and they have different functions but the most effective way to test it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms if the sensor is in full operation. If you're experiencing issues with this component, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed I noticed a significant reduction in power. It was like the engine had run out of gas. Or, my injectors were not firing. I took out the spark plugs this morning, three were soaked with gasoline and the 4th was dry. When i crank 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 leap out, however the 4th one stays closed. I checked the ground connection of ECU pins 14,30 and 48/55. I got zero ohm. Therefore, i think the issue is in another place.
I also tried to reset PID without success. The car can start when the G28 is disconnected and it runs perfectly when it is connected but it still is experiencing intermittent misfires at higher RPM. The coolant sensor (G62), even when it is unplugged, shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is zero.
I'm not sure what to do, but i feel i have pretty much ruled out everything else. But i am afraid I may have missed something. Let me know should you have any suggestions! 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 are used in the 80, 100, 200, UrS and RS2 cars which is why you can easily locate one at a salvage yard or from a 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's end up) and 2 (2nd from left on the black end of the connector). 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 decisions about fuel injector timing etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you have a problem with either one of these, the diagnostic scanner will display codes that could lead to an engine shutdown.
The signs of a failing G28 sensor are an inaccurate gearbox rev counter and gears that shift faster than normal, and/or a misfire when you are in gear. If you are experiencing any of these problems, it is most likely that your sensor is going bad and needs replacing. They're inexpensive and easy to locate particularly in the case of an Bosch model like ours. Alternatively, the GM version of this component is also a good option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your car. It is an important part of the transmission in your Audi, as it transmits information to the ECU about how fast or slow the engine of the car is turning. This sensor could cause the transmission to fail and other components of the car to be affected.
The G5 engine speed sensor is situated on the edge of the transmission just above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 through a grey wire. The ECU utilizes this signal to control the amount of fuel and boost, and also to timigrate. It also transmits it to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity of the sensor to the tachometer. Also, 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 and pin T26a/12. You should see an average resistance of 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 range, beginning with the 1985 MC and up to the 1997 UrS AN and 1995 RS2 DU So, you may find good ones in wrecking yards.