4 Dirty Little Secrets About Audi G28 Industry Audi G28 Industry
4 Dirty Little Secrets About Audi G28 Industry Audi G28 Industry
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How to Replace an Audi G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor is located at the top of the transmission just above the flywheel ring gear. It transmits a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends signals to ECU pin T55/49 through an uncolored wire. The ECU uses this information to control fuel and boost. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can start spark and injectors according to the situation.
If this sensor fails to function, 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 indicate an issue with the chain or a jumped chain link in the upper chain. However, the code won't appear on its own without additional information from other sensors (G4 and G40).
Testing can be a bit difficult since there are two connector pins and they serve different purposes however the best method of testing it is by measuring resistance between the sensor and the ECU. It should read around 1000 ohms when it is at full operation. If you're having issues with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed, i noticed a huge drop in power. It was like the engine had run out of gas. Or my injectors weren't firing. In the morning, i removed the spark plugs. Three were soaked with gazoline and the fourth was dry. When i crank the engine with no sparks, i place a tissue on the top of each hole in the injector and the 3 that were drenched in gazoline pop out, but the 4th one stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found 0ohm. So i assume the problem is in another place.
I also tried to reset the PID but without success. The car will start if the G28 is unplugged and here runs fine when it is connected however it has the intermittent misfire issue at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows a temperature of -49c. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar, whereas the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do. I feel like i've pretty much all other possibilities out. However, i'm afraid that I might have missed something. If anyone has suggestions, please chime in! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter is identical to the G4 and both are used in the 80, 100, 200, UrS and RS2 cars so you can easily find one at a junkyard or at a parts store. It is easy to test them - just put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines are equipped with an ECU that needs to know the speed and position of the crankshaft to make decisions regarding fuel injector timing etc. here It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you encounter a problem with either of these, the diagnostic scanner will display the codes that could trigger the engine shutting down.
The signs of a failing G28 sensor are an inaccurate rev counter in the gearbox the website gears are shifting faster than normal and/or misfiring when you are in gear. If you have any of these issues it is likely that your sensor is failing and requires replacement. The good news is they are very cheap and readily available particularly in the case of an Bosch sensor, which is what ours are. Alternatively, the GM version of this unit is also a great option.
5. Tachometer
A malfunctioning engine speed sensor could be a cause for numerous issues with your vehicle. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the vehicle's crankshaft is turning. If this sensor fails, it can cause problems for the transmission as well as the rest of the car's components.
The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It more info sends signals via an uncolored wire to the ECU pin T55/49. The ECU utilizes this signal to control 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 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 an average website resistance of 1000 ohms between these two points. This is a common feature across the Audi 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN and 1995 RS2 DU You may also find them in wrecking yards.