A Brief History Of Audi G28 History Of Audi G28
A Brief History Of Audi G28 History Of Audi G28
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How to Replace an Audi G28 Engine Speed Sensor
In this video, Charles the Humble Mechanic shows how to replace the G28 engine speed sensor. The sensor is located on the outside of the transmission over the flywheel gear. It transmits a signal to the ECU through the grey wire T55/49 and then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
The grey wire is located at the edges of the transmission, directly above the flywheel ring. The sensor transmits signals through the grey wire to pin T55/49. The ECU then utilizes this information to regulate the boost, fuel, and timig. It also sends an alert to the G5 Tachometer located in the instrument cluster.
The sensor is used to correlate the G40 Camshaft position Sensor. The ecu must know when the crankshaft is TDC and the location of the camshaft so it can trigger spark and injectors in the right way.
If this sensor fails, the ECU will display a P00160 code which means the Crank Shaft and Intake Camshaft are out of sync and possibly indicating chain stretch or a jumped link on the upper timing chain. The code won't show without the additional information provided by other sensors (G4 or G40).
It's a bit tricky to test since there are several 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 fully functional, it should read approximately 1000 ohms. Look for signs of coolant or oil in the connector bay if you are experiencing issues with this part.
2. Injectors
Yesterday, when accelerating from highway paytoll at maximum speed, i noticed a huge decrease in power. It was as if the engine was running out of gas. Or my injectors were not firing. I pulled out the spark plugs this morning, 3 were soaked in gasoline, and the fourth was dry. I put tissue over each hole in the injector and when i start the engine without sparks, the three with gazoline jump out. The 4th one remains shut. I inspected the ground connection on ECU pins 14/55/30/55/48/55/14/55/48/ I got zero ohm. I think the issue is elsewhere.
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 problem still occurs at higher RPM. The temperature sensor for coolant (G62) shows the wrong temp value -49c even when i unplug it. I also noticed that the oil gauge in the cockpit shows 2 bars while the actual pressure is 0.
I'm not certain what to do, as i think i've check here pretty much completely ruled out all other possibilities. But i'm worried that i might have missed something. Let me know should you have any suggestions! TIA!
3. Fuel Pump
The fuel pump of the g28 receives a signal from the RPM sensor. The GM-style sensor 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 junkyard or from a 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 end up) spare audi key cost and 2 (2nd from left on the black connector's end). They should be infinite ohms.
4. ECU
The ECU in our 20vt turbo (3B AAN ABY) engines must know the position and speed the crankshaft to make decisions regarding fuel injector timing, etc. It uses a Crank Position Sensor G4 and an Engine Speed Sensor G28 to achieve this. If either of these goes wrong, you will receive codes on the diagnostic scanner that can lead to engine shutdown.
A damaged G28 sensor can cause an inaccurate speed counter for your gearbox, a gearbox that shifts faster than normal, and/or a misfire while in the gear. more info It is possible that the sensor is failing and requires to be replaced if you encounter any of these symptoms. The good thing is that they are quite affordable and readily available, especially when you're looking at an Bosch model, like ours. Alternately, the GM version of this component is also a good choice.
5. Tachometer
A malfunctioning engine speed sensor could be the reason behind numerous issues with your vehicle. It is a crucial part of the Audi's transmission as it sends 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 other car's components.
The G5 engine speed sensor is situated on the edge of the transmission, above the flywheel ring gear and transmits a signal to the ECU at pin T55/49 via a grey wire. The ECU is then able to process this signal to control fuel, timig and boost and then sends it on to the G5 tachometer in the instrument cluster. You can check here test for sensor failure by checking continuity from the sensor to the tachometer. Additionally, you can check continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79trace [79]), and between pin T6a/1 as well as pin T26a/12. You should observe around 1000 ohms of resistance between those points. This is a typical part across the Audi 80, 100 200, UrS and RS2 range from 1985 MC through the 1997 UrS AAN and 1995 RS2 ADU. Good ones audi lost key might be availble in wrecking yards.