"The Ultimate Cheat Sheet" On Audi G28
How to Replace an replacement audi a3 key G28 Engine Speed Sensor
Charles the Humble Technician shows how to replace the G28 Engine Speed Sensor. The sensor replacement audi a3 key is located at the edge of transmission, above the flywheel gear. It sends a signal to the ECU via a grey wire (T55/49) which is then sent to the tachometer in the instrument cluster.
1. Engine Speed Sensor
The grey wire is located on the edge of transmission, just above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an alert to the G5 Tachometer within the instrument cluster.
The sensor serves as a reference for comparing with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can start spark and injectors according to the situation.
If this sensor fails the ECU will show a P00160 code which means the Crank Shaft and Intake Camshaft aren't in sync and possibly indicating the chain stretching or a jump link on the upper chain of timing. The code won't appear without the additional information supplied by other sensors (G4 or G40).
It's a bit tricky to test because there are various pins on the connector, and each one has different functions. The most effective method to test it is to measure the resistance between the ECU and the sensor. When the sensor is operational, it should read approximately 1000 ohms. Look for signs of coolant, or oil in the connector bay if there are issues with this component.
2. Injectors
Yesterday accelerating full speed from highway paytoll, i experienced massive power loss like the engine is running out of gas or the injectors are not firing any more. This morning i pull out the spark plugs, three were drenched with gazoline the 4th one was dry. I put a piece of tissue over each injector hole and when I start the engine with no sparks, the three with gazoline jump right out. The 4th one stays closed. I checked the ground connection on ECU pins 14/55, 30/55 and 48/55. i get 0ohm. I'm assuming the issue is in another place.
I also tried to reset the PID with no success. The car will start when the G28 is disconnected, but it works fine when the G28 connected. However, the intermittent misfire problem persists at higher RPM. The temperature sensor for the coolant (G62) shows the wrong temperature value of -49c, even if I unplug it. I also noticed that the oil pressure gauge in the cockpit is showing 2 bar when the actual pressure is 0.0 if i crank up the engine.
I'm not sure what to do. I think I've eliminated everything else. I'm worried that i might have missed something. If anyone has any ideas please chime in! TIA!
3. Fuel Pump
The fuel pump in the g28 receives signals from the RPM sensor. The GM-style sender is identical to the G4 and both are used in the 80, 100 200, UrS and RS2 cars so you can easily find one at a wrecking yard or at a parts store. It is simple to test them: simply put your DMM into resistance mode and measure the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They must be infinite ohms.
4. ECU
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. In order to do this it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either of these sensors, the diagnostic scanner will display codes that could cause an engine shutdown.
A failing G28 sensor could result in an inaccurate gearbox speed counter and a gearbox which shifts faster than normal, or a misfire while in gear. If you experience any of these issues it is most likely that your sensor is failing and should be replaced. They're cheap and easy to find, especially in the case of a Bosch model like ours. Alternatively, GM's version of this part is an excellent choice.
5. Tachometer
A faulty engine speed sensor could be the cause of a slew of issues with your car. It's an essential component of the Audi's transmission as it sends information to the ECU about how fast or slow the car's crankshaft is turning. If the sensor fails, it could affect the performance of the transmission and the other car's components.
The G5 engine sensor is located near the edge of the transmission, just above the flywheel ring. It transmits a signal via a gray wire to the ECU pin T55/49. The ECU utilizes this signal to control fuel and boost, and also to timigrate. It also sends it to the G5 Tachometer inside the instrument cluster. You can check the sensor for failure by checking continuity between it and the tachometer. You can also check continuity between ECU pin T55/49 and the instrument cluster connection to pin T6a/1 (trace [79trace [79]) and between pin T6a/1 and the instrument cluster pin T26a/12. You should see approximately 1000 ohms resistance between those two pins. This part is common across the audi a1 key 80-100-200-RS2 model, ranging from the 1985 MC up to the 1997 UrS AN and the 1995 RS2 Du So, you may find some good ones in wrecking yards.