The 10 Most Infuriating Audi G28 Fails Of All Time Could've Been Prevented
The 10 Most Infuriating Audi G28 Fails Of All Time Could've Been Prevented
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How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located near the transmission's edge over the flywheel gear. It transmits a signal to the ECU via an uncolored wire (T55/49), then to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the edge of transmission, above the flywheel ring. The sensor sends a signal via 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 located in the instrument cluster.
The sensor is used to link with the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is located so that it can trigger spark and injectors accordingly.
If this sensor fails to function, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in alignment with the Intake Camshaft. It could also indicate the possibility of a chain stretch or jumped chain link in the upper timing chain. The code will not appear without the additional information supplied by other sensors (G4 or G40).
Testing can be a bit difficult since there are two connector pins, and they perform different functions but the best method of testing it is to measure the resistance between the sensor and the ECU. If the sensor is functional, it should read about 1000 ohms. If you are having problems with this component, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at a high speed I noticed a significant reduction in power. It was like the engine was running out of gas. Or, my injectors weren't firing. I took out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was unclean. I put a piece of tissue over each injector hole and when I turn the engine on without sparks, the ones that have gazoline pop right out. The 4th one remains shut. I tested the ground connection on ECU pins 14/55,30/55 and 48/55 I get 0ohm. So i assume get more info the problem is somewhere else.
I also tried to reset PID without success. The car can start if the G28 is unplugged and runs fine when it is plugged in but it still has intermittent misfire issues at higher RPM. The coolant sensor (G62), even when it is unplugged, shows an ice temperature of -49c. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar when read more the actual pressure is 0.0 when i rev the engine.
I don't know what to do. I believe that I've all other possibilities out. However, i'm afraid that i might have missed something. Let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 receives a signal from the lost audi key RPM sensor. The GM-style sensor is identical to the G4 and they both work 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. It is easy to test them: simply put your DMM into resistance mode and determine the distance between pins 1 and 2 (with the bump at the connector end facing up). They must be infinite Ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines requires to know both the speed and position of the crankshaft to determine fuel injector timing, etc. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If either of these sensors go wrong, you will receive codes on the diagnostic scanner that could cause engine shut down.
A malfunctioning G28 sensor could cause an inaccurate gearbox speed counter, a gearbox that shifts faster than normal, and/or an unfire when in gear. If you experience any of these issues, it is likely that your sensor is failing and requires replacement. The good thing is that read more they are very affordable and readily available particularly in the case of the Bosch model, like ours. Alternately, the GM version of this unit is also a good option.
5. Tachometer
A faulty engine speed sensor could be a cause for many problems in your vehicle. It's a crucial component of the transmission in your Audi, as get more info it transmits information to the ECU regarding how fast or slow the engine of the car is spinning. If the sensor fails, it could disrupt the performance of the transmission, as well as the other car's components.
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 uses this signal to regulate the flow of fuel and boost as well as timig. It also transmits it to the G5 Tachometer located in the instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. You can also verify 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 detect the resistance to be around 1000 ohms in these areas. This is a standard part that is found across the Audi 80, 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU so good ones might be availble in wrecking yards.