What's The Most Important "Myths" About Audi G28 Might Be True
What's The Most Important "Myths" About Audi G28 Might Be True
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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 located at the top of the transmission, above the flywheel ring gear. It transmits a signal to the ECU via the grey wire (T55/49) which is then sent to the tachometer within the instrument cluster.
1. Engine Speed Sensor
The sensor is located at the edge of the transmission just above the flywheel ring gear the G28 Engine Speed Sensor sends a signal to ECU pin T55/49 via a grey wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends an alert to the G5 Tachometer in instrument cluster.
The sensor is used to connect the G40 Camshaft position Sensor. The ecu must know when the crankshaft reached TDC and also the location of the camshaft to trigger the spark and injectors.
If this sensor fails when it fails, 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 a chain stretch or a jump in the chain link of the upper chain of timing. However, the error code won't appear on its own, without additional information from other sensors (G4 and G40).
Testing is a bit tricky since there are two pins for the connector and they have different functions however the best way to test it is to measure resistance between the sensor and the ECU. When the sensor is fully operational, it should read about 1000 ohms. Examine for evidence of coolant or oil in the connector bay if you are experiencing problems with this part.
2. Injectors
Yesterday, while accelerating from the highway paytoll at maximum speed I noticed a massive decrease in power. It was as if the engine was running out of gas. Or my injectors weren't firing. I pulled out the spark plugs this morning and found that 3 were drenched in gasoline and the fourth was unclean. When i crank the engine, there are no sparks, I put a piece of tissue on the top of each of the injector holes and the 3 that were drenched in gazoline leap out, however the 4th stay shut. I checked the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. I think the issue is in another location.
I also tried to reset the PID without success. The car will start when the G28 is disconnected, but it is running fine with the G28 plugged in. However the intermittent misfire issue still occurs at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. Also i noticed that the gauge for oil pressure in the cockpit is showing 2 bar while the actual pressure is 0.0 if i crank up the engine.
I don't know what to do. I feel like i've pretty much ruled everything else out. I'm concerned that i may have missed something. If anyone has suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style transmitter functions similarly to the G4 sender and both work on the 80,100,200, UrS, and RS2 vehicles. It is easy to find the spare in a salvage shop or a parts store. Test them out - put your DMM in resistance mode and measure between pins 1 (with the bump on the connector's end up) and 2 (2nd from left on the black connector's website side). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft to make decisions regarding timing of the fuel injectors, etc. It utilizes a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If you are experiencing issues with either of these sensors, the diagnostic scanner will display codes more info that could cause the engine shutting down.
A malfunctioning G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts faster than normal, and/or a misfire in the gear. It is probable that your sensor is failing and needs to be replaced if you experience any of these signs. They're inexpensive and easy to locate, especially in the case of an Bosch unit like ours. Alternatively, GM's version read more of this component is a good option.
5. Tachometer
A malfunctioning engine sensor can cause a number of problems within your vehicle. It is an important part of the transmission of your Audi, as it transmits information to what is the audi advanced key the ECU regarding how fast or slowly the engine is spinning. This sensor could cause the transmission to malfunction and other components in the car to be affected.
The G5 engine sensor is located at website the edge of the transmission, just above the flywheel ring. It sends an electrical signal through gray wire to ECU pin T55/49. The ECU uses this signal to regulate the flow of fuel and boost as well as timig. It also sends it to the G5 Tachometer inside the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. Also, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [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 standard 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 parts could be found in wrecking yards.