How to Replace an audi etron key G28 Engine Speed Sensor
Charles the Humble Technician shows you 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 an uncolored wire T55/49, then to the tachometer in the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission above the flywheel ring gear the G28 Engine Speed Sensor sends an electrical signal to ECU pin T55/49 via a grey wire. The ECU uses this information to regulate boost and fuel. It also sends a signal to the G5 Tachometer located in the instrument cluster.
(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/11/happy-african-american-businessman-holding-car-key-2022-12-16-16-36-17-utc-min-scaled.jpg)The sensor is used to link the G40 Camshaft position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is so it can activate spark and injectors in the right way.
If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched or a jump link on the upper chain of timing. However the code will audi key fob not working be displayed 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 the sensor is at full operation. If you're having issues with this component, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed I noticed a significant decrease in power. It was like the engine was running out of gas. Or, my injectors were not firing. I took out the spark plugs this morning and found that 3 were soaked in gasoline, and the 4th was dry. When I start the engine, there are no sparks, i place a tissue on the top of each hole in the injector and the 3 drenched with gazoline leap out, however the 4th stays closed. I tested the ground connection of ECU pins 14,30 and 48/55. I found zero ohm. I think the issue is somewhere else.
I also tried to reset PID but without success. The car is able to start when the G28 is disconnected and is running fine when it is connected however it has the intermittent misfire issue at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature of that is -49c even after unplugging it. I also noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.
I'm not sure what to do, but i believe that i've eliminated everything else. But i'm worried that I may have missed something. If anyone has any suggestions, please share them! TIA!
3. Fuel Pump
The fuel pump of the g28 gets a signal from the RPM sensor. The GM-style transmitter functions similarly to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. It is easy to find an extra in a wrecking shop or a parts store. Testing them is easy by putting your DMM in resistance mode and measure between pins 1 (with the bump on the connector end up) and 2 (2nd from the left on the black end of the connector). They must be infinite Ohms.
4. ECU
The ECU of our 20vt turbo (3B AAN ABY ADU) engines needs to know both the speed and position of the crankshaft to make decisions regarding timing of the fuel injector, etc. 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 show codes that could cause an engine shut down.
Some of the signs of a malfunctioning G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal, and/or a misfire when you're in gear. If you experience any of these issues, it is likely that your sensor is going bad and needs replacing. They're inexpensive and easy to locate, especially in the case of an Bosch unit like ours. Alternately, GM's version this part would be an option.
5. Tachometer
A failing engine speed sensor could be the cause of numerous issues with your car. It is a crucial part of your audi spare keys's transmission, because it communicates to the ECU about how fast or slow the vehicle's crankshaft is spinning. This sensor can cause the transmission to malfunction and other components of the car key cover audi to be affected.
The G5 engine speed sensor is located on the edge of the transmission just above the flywheel ring gear and sends a signal to the ECU at pin T55/49 via an uncolored wire. The ECU utilizes this signal to regulate the flow of fuel and boost as well as timig. It also transmits it to the G5 Tachometer in instrument cluster. You can test the sensor for failure by examining the continuity between it and the tachometer, between the ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see around 1000 ohms of resistance between these two points. This is a standard component across the audi tt key case 80 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU, so the best ones could be available in wrecking yards.(Image: https://g28carkeys.co.uk/wp-content/uploads/2023/10/young-couple-holding-the-keys-of-a-new-car-select-2023-04-03-23-35-08-utc-scaled.jpg)
