Why Nobody Cares About Audi G28
How to Replace an audi key G28 Engine Speed Sensor
In this video Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission just above the flywheel gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer located on the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, directly above the flywheel ring. The sensor transmits an electrical signal through the grey wire to pin T55/49. The ECU then uses this information to control the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer in instrument cluster.
The sensor is used as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to be aware of when the crankshaft has reached TDC and also the position of the camshaft, in order to activate the spark and injectors.
If this sensor fails the ECU will throw the P00160 error, which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating the chain is stretched or a jump link on the upper timing chain. The code won't appear without the additional information supplied by other sensors (G4 or G40).
Testing is a bit tricky as there are two different connector pins and they perform different functions however the best way to test 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 are having problems with this sensor, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, when accelerating from highway paytoll at full speed I noticed a massive decrease in power. It was like the engine was running out of gas. Or my injectors weren't firing. I pulled out the spark plugs this morning, three were soaked in gasoline, and the 4th was dry. When i crank the engine, there are no sparks, i place a tissue on top of each injector hole, the 3 drenched with gazoline pop out, but the 4th stay shut. I tested the ground connection of ECU pins 14,30 and 48/55. I found 0ohm. So i assume the problem is somewhere else.
I also tried to reset PID but without success. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However the intermittent misfire issue continues to occur at higher RPM. The temperature sensor for coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars but the actual pressure is 0.
I'm not sure what to do. I believe that I've ruled everything else out. But i'm worried that I might have missed something. If anyone has suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal sent from the RPM sensor. The GM-style transmitter is the same as the G4 and both are used 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. Test them out to do - just put your DMM in resistance mode and measure the resistance between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's side). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that needs to know the position and speed of the crankshaft to make decisions regarding timing of the fuel injector, for example. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these sensors go wrong, you will receive codes on the diagnostic scanner that could cause engine shut down.
The signs of a failing G28 sensor are an inaccurate gearbox rev counter the gears are shifting faster than normal, and/or a misfire when in gear. If you experience any of these problems, it is likely your sensor is deteriorating and should be replaced. The good news is that they are very affordable and readily available, especially when you're looking at a Bosch unit which is what ours are. Alternately, GM's version this part is an option.
5. Tachometer
A failing engine speed sensor could be a cause for a slew of issues with your car. It's an essential component of the Audi Key Replacement Cost's transmission because it communicates to the ECU about how fast or slow the vehicle's crankshaft is turning. If this sensor fails, it could disrupt the performance of the transmission as well as the other car's components.
The G5 engine sensor is located near the edge of transmission, above the flywheel ring. It transmits signals via a gray wire to the ECU pin T55/49. The ECU is then able to process this signal to regulate fuel, audi A1 key timig, and boost as well as transmitting it to the G5 tachometer in the instrument cluster. You can check the sensor for any failure by checking the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection on pin T6a/1 (trace [79trace [79]) as well as between T6a/1, and the instrument cluster pin T26a/12. You should see the resistance to be around 1000 ohms in these areas. This is a typical part that is found across the audi key fob not working 80 100, 200, UrS and RS2 range from 1985 MC to the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.