"The Ultimate Cheat Sheet" For Audi G28
"The Ultimate Cheat Sheet" For Audi G28
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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 the ECU via a grey wire (T55/49) which is then sent to the tachometer located in the instrument cluster.
1. Engine Speed Sensor
The grey wire is situated on the outside of the transmission, above the flywheel ring. This sensor sends a signal via the grey wire to pin T55/49. The ECU uses this information to control boost and fuel. It also sends a signal to the G5 tachometer inside the instrument cluster.
The sensor serves as a reference to correlate with the G40 Camshaft Position Sensor. The ecu needs to know when the crankshaft is TDC and where the camshaft is located so that it can activate spark and injectors in the right way.
If this sensor fails the ECU will throw an error code P00160 which indicates that the Crank Shaft and Intake Camshaft are out of sync, possibly indicating the chain is stretched or a jump link on the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).
It can be a bit difficult to test since there are different pins on the connector and each one has different functions. The best method for doing this is by measuring the resistance between the ECU and the sensor. It should read around 1000 ohms when the sensor is operating at its maximum. If you're experiencing issues with this part, check for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday, while accelerating at full speed from the highway paytoll, i experienced a big cut in power like the engine is out of gas or the injectors aren't firing any more. I pulled out the spark plugs this morning, 3 were soaked with gasoline and the fourth was unclean. When I start the engine without sparks i put tissue on top of each injector hole and the 3 drenched with gazoline jump out but the 4th one stays shut. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got zero ohm. I'm assuming the issue is elsewhere.
I also tried to reset the PID but with no luck. The car will start when the G28 is disconnected, but it runs fine with the G28 plugged in. However, the intermittent misfire problem still occurs at higher RPM. The coolant sensor (G62), even if it is not plugged in, shows temperatures of -49c. I also website noticed that the oil gauge in the cockpit shows 2 bar but the actual pressure is 0.
I'm not sure what to do. I feel like i've pretty much eliminated everything else. But i'm worried that i might have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump of the g28 receives signals from the RPM sensor. The GM-style transmitter is the same as the G4 and both function in the 80 100 200, UrS and RS2 cars which is why you can easily locate one at a junkyard or in a local parts store. Test them out by putting your DMM in resistance mode and take measurements between pins 1 (with the bump on the connector's side up) and 2 (2nd from left on the black connector's end). They should be infinite Ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY, and ADU) engines have an ECU that needs to know the speed and position of the crankshaft in order to make decisions about timing of the fuel injectors, etc. To accomplish this, it makes use of a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you are experiencing issues with either one of these, the diagnostic scanner will show codes that could lead to an engine shut down.
The signs of a failed G28 sensor include an inaccurate rev counter for the gearbox, gears shifting quicker than normal and/or misfiring when you are in gear. It is get more info possible that the sensor is failing and needs to be replaced if you notice any of these signs. The good news is that they are very affordable and easily accessible particularly if you're looking at an Bosch unit which is what ours are. If you prefer, GM's version of this component is an option.
5. Tachometer
A damaged engine sensor could cause a myriad of issues in your vehicle. It is a crucial part of your Audi's transmission, because it communicates to the ECU about how the car's crankshaft is turning. When this sensor fails, it can disrupt the performance of the transmission and the rest of the car's components.
The G5 engine sensor is located at the edge of transmission, above the flywheel ring. It transmits an electrical signal through an uncolored wire to the ECU pin T55/49. The ECU then uses genuine audi key replacement and processes this signal to control fuel, timig, and boost, and also sends it on to audi spare key the G5 Tachometer located in the instrument cluster. You can determine if the sensor is in failure by examining the continuity from the sensor to the tachometer. You can also check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]) and between pin T6a/1 as well as pin T26a/12. You should see an average resistance of 1000 ohms in these areas. This is the same how much is a replacement audi key across the Audi 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS An and 1995 RS2 DU You may also find them in wrecking yards.