How to Replace an Audi G28 Engine Speed Sensor<br /><br />In this video, Charles the humble mechanic demonstrates how to replace the G28 engine speed sensor. This sensor is located on the outside of the transmission over the flywheel gear. It sends a signal to the ECU via the grey wire (T55/49), then to the tachometer within the instrument cluster.<br /><br />1. Engine Speed Sensor<br /><br />Located on the edge of the transmission just above the flywheel ring gear G28 Engine Speed Sensor sends a signal to ECU pin T55/49 using an uncolored wire. The ECU then uses this information to control the boost, fuel, and timig. It also sends a signal to the G5 tachometer inside the instrument cluster.<br /><br />The sensor is used 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 in the right way.<br /><br />If this sensor fails when it fails, the ECU will display a P00160 error message. This indicates that the Crank Shaft is not in sync with the Intake Camshaft. It could also be a sign of the possibility of a chain stretch or jumped chain link in the upper timing chain. The code won't show without the additional information supplied by other sensors (G4 or G40).<br /><br />It can be a bit difficult to test because there are different pins on the connector and they all have different functions. The most effective method to test it is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is at full operation. Look for signs of coolant or oil in the connector bay if you have issues with this component.<br /><br />2. Injectors<br /><br />Yesterday, while accelerating from the highway paytoll at full speed I noticed a massive drop 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 drenched in gasoline and the fourth was dry. When i crank the engine without sparks i put tissue on top of each injector hole and the 3 that were drenched in gazoline leap out, however the 4th stays shut. I checked the ground connection of ECU pins 14,30 and 48/55. I got 0ohm. Therefore, i think the issue is somewhere else.<br /><br />I also tried to reset the PID but without success. The car will start when the G28 is disconnected, but it works fine when the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62), even when unplugged, still shows a temperature of -49c. I also noticed that the oil gauge in the cockpit shows 2 bars when the actual pressure is 0.<br /><br />I'm not sure what to do, but i believe that i've completely ruled out all other possibilities. I'm concerned that i may have missed something. Please let me know should you have any suggestions! TIA!<br /><br />3. <a href="https://www.g28carkeys.co.uk/audi-car-key-replacements-near-me/">audi a5 replacement key</a> on the g28 is activated by a signal from the RPM sensor. The GM-style transmitter is identical to the G4 sender, and both operate on the 80,100,200, UrS, and RS2 vehicles. You can easily locate an extra in a wrecking shop or parts store. Test them out by putting 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 must be infinite Ohms.<br /><br />4. ECU<br /><br />Our 20vt turbo (3B, AAN, ABY and ADU) engines have an ECU that must know the speed and position of the crankshaft to make decisions about timing of the fuel injector, for example. To do this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these, the diagnostic scanner will show codes that could cause an engine shut down.<br /><br />A damaged G28 sensor could cause an inaccurate speed counter for the gearbox or a gearbox that shifts more quickly than normal, or a misfire in the gear. It is likely that your sensor is failing and needs to be replaced if you encounter any of these signs. The good thing is that they are quite affordable and easily accessible particularly when you're looking at the Bosch model, which is what ours are. If you prefer, GM's version of this component is a good option.<br /><br /><br /><br />5. Tachometer<br /><br />A failing engine speed sensor could be a cause for a slew of issues in your car. It's an essential component of your Audi's transmission, as it sends information to the ECU about how fast or slow the car's crankshaft is spinning. This sensor can cause the transmission to fail and other components in the car to be affected.<br /><br />The G5 engine speed sensor is situated 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 then processes this signal to regulate fuel, timig, and boost, and also transmitting it to the G5 tachometer in the 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 on pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. There should be an average resistance of 1000 ohms in these areas. This is a standard component across the Audi 80, 100 200, UrS and RS2 range from 1985 MC until the 1997 UrS AAN and 1995 RS2 ADU. Good ones could be available in wrecking yards.<br /><br />