20 Myths About Audi G28: Debunked
20 Myths About Audi G28: Debunked
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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. This sensor is situated on the outside of the transmission just above the flywheel gear. It transmits a signal to the ECU through a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission, above the flywheel ring gear, the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 using an uncolored wire. The ECU utilizes this information to control fuel and boost. It also sends a signal to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate 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 start spark and injectors in the right way.
If this sensor fails when it fails, the ECU will display a P00160 error code. This indicates that the Crank Shaft is out of alignment with the Intake Camshaft. It could also be a sign of a chain stretch or a jumped chain link in the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).
It's a bit tricky to test as there are various pins on the connector and each has its own functions. The best way to do it is by measuring the resistance between the ECU and the sensor. If the sensor is functional, it should read about 1000 ohms. If you are having problems with this sensor, look for signs of coolant or oil in the connector bay.
2. Injectors
Yesterday, as i was accelerating off the highway paytoll at maximum speed I noticed a significant reduction in power. It was like the engine was running out of gas. Or, my injectors were not firing. Today, i pulled out the spark plugs. Three were drenched with gazoline the fourth one was dry. When I crank the engine without sparks i put tissue on the top of each hole in the injector and the 3 drenched with gazoline jump out but the 4th one stays shut. I tried to test the ground connections of ECU pins 14,30 and 48/55. I got 0ohm. So i assume the problem is somewhere else.
I also tried to reset the PID but without success. The car can start if the G28 is unplugged and is running fine when it is connected however it has intermittent misfire issues at higher RPM. The coolant sensor (G62) even when it is unplugged, shows a temperature of -49c. Also, i noticed that the oil pressure gauge in the cockpit shows 2 bar, whereas the actual pressure is 0.0 when I crank up the engine.
I don't know what to do. I believe that I've ruled everything else out. But audi spare key replacement i'm worried that i might have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the 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 junkyard or from a parts store. It is easy to test audi a1 key them - simply put your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump at the connector end facing upwards). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that must be aware of the speed check here and position of the crankshaft in order to make decisions about timing of the fuel injector, for example. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. lost audi keys If you have a problem with either of these sensors, the diagnostic scanner will display the codes that could trigger the engine shutting down.
Some of the symptoms of a failed G28 sensor are an inaccurate rev counter in the gearbox the gears are shifting faster than normal and/or misfiring when you are in gear. If you experience any of these issues it is likely that your sensor is deteriorating and requires replacement. They are cheap and easy-to-find particularly if they're an Bosch unit like ours. Alternatively, the GM version of this part is also a good choice.
5. Tachometer
A failing engine sensor could cause a number of problems in your vehicle. It's an essential component of the Audi's transmission because it communicates to the ECU about how the car's crankshaft is spinning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine speed sensor is located on the outside of the transmission above the flywheel ring gear. It sends a signal to the ECU at pin T55/49, via a grey wire. The ECU is then able to process the signal to control fuel, timig and boost and then sends it on to the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. Also, you get more info 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. It should show approximately 1000 ohms of resistance between those two pins. This is a typical component 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.