10 Top Mobile Apps For Audi G28
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. The sensor is situated near the edges 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 in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated at the edges of the transmission, just above the flywheel ring. This sensor sends an electrical signal through the grey wire to pin T55/49. new audi key G28 Car Keys uses this information to regulate the amount of fuel and boost. It also sends signals to the G5 tachometer in the instrument cluster.
The sensor is used to link the G40 Camshaft position Sensor. The ecu has to know when the crankshaft has reached TDC, and the position of the camshaft, to trigger the spark and injectors.
If this sensor fails the ECU will show the P00160 error, which means the Crank Shaft and Intake Camshaft are not in sync and possibly indicating the chain stretching or a jump link on the upper timing chain. However the code will not appear on its own without additional information from other sensors (G4 and G40).
Testing is a bit tricky because there are two connector pins and they have different functions but the best way to test it is to measure the resistance between the sensor and the ECU. It should read around 1000 ohms when the sensor is operating at its maximum. If you're having issues with this component, look for evidence of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating from the highway paytoll at full speed, i noticed a huge drop in power. It was like the engine had run out of gas. Or my injectors were not firing. Today, i pulled out the spark plugs, 3 were drenched with gazoline the 4th one was dry. I put a piece of tissue over each hole in the injector and when I turn the engine on without sparks, the three that have gazoline pop right out. The 4th one stays closed. I inspected the ground connection on ECU pins 14/55,30/55 and 48/55 i get 0ohm. Therefore, i think the issue is elsewhere.
I also tried to reset the PID without success. The car is able to start when the G28 is unplugged and runs fine when it is connected, but still has intermittent misfire issues at higher RPM. The coolant sensor (G62) even when unplugged, still shows an ice temperature of -49c. Also i noticed that the gauge for oil pressure in the cockpit shows 2 bar while the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do, but i think i've pretty much ruled out everything else. But i'm worried that I may have missed something. Please let me know If you have any suggestions! TIA!
3. Fuel Pump
The fuel pump in the g28 can be activated by a signal sent by the RPM sensor. The GM-style sender is the same as the G4 and both function in the 80, 100 200, UrS and RS2 cars so you can easily find one at a salvage yard or in a local parts store. It is simple to test them - 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 the left on the black connector's end). They must be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines are equipped with an ECU that has to know the speed and position of the crankshaft to make decisions about fuel injector timing etc. It makes use of a Crank Position Sensor G4 and an Engine Speed Sensor G28 to accomplish this. If you are experiencing issues with either one of these, the diagnostic scanner will display codes that could cause the engine shutting down.
A malfunctioning G28 sensor could cause an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire in gear. It is possible that the sensor is failing and needs to be replaced if you experience any of these signs. The good news is that they are quite affordable and easy to find, especially in the case of an Bosch sensor, like ours. If you prefer, GM's version of this part would be an option.
5. Tachometer
A failing engine sensor could cause a myriad of issues within your vehicle. It is a crucial part of your Audi's transmission, since it relays information to the ECU about how the car's crankshaft is spinning. If this sensor fails, it could affect the performance of the transmission and the rest of the car's components.
The G5 engine sensor is located at the outskirts of the transmission, over the flywheel ring. It transmits an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU uses this signal to regulate the flow of fuel and boost as well as timig. It also relays it to the G5 Tachometer inside the instrument cluster. You can check the sensor for failure by examining the continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection via pin T6a/1 (trace [79trace [79]) and between T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms resistance between these two points. This is the same across the Audi 80-100-200-RS2 series, starting from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU So, you may find them in wrecking yards.