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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. This sensor is located on the outside of the transmission, above the flywheel gear. It sends a message to the ECU via a grey wire T55/49, then to the tachometer on the instrument cluster.
1. Engine Speed Sensor
It is located on the outside of the transmission, above the flywheel ring gear G28 Engine Speed Sensor audi Key fob not working sends an electrical signal to ECU pin T55/49 via the grey wire. The ECU then utilizes this information to regulate the flow of fuel, timig and boost. It also sends an indication to the G5 Tachometer located in the instrument cluster.
The sensor is used as a reference point to connect with the G40 Camshaft Position Sensor. The ecu must know when the crankshaft is TDC and where the camshaft is so it can trigger spark and injectors in the right way.
If this sensor fails to function, the ECU will display a P00160 error message. This means that the Crank Shaft is out of line with the Intake Camshaft. It could also be a sign of a chain stretch or a jump in the chain link of the upper timing chain. The code will not appear without the additional information provided by other sensors (G4 or G40).
Testing is a bit challenging as there are two different connector pins and they serve different purposes but the best method to test it is by measuring resistance between the sensor and the ECU. When the sensor is functional, it should read approximately 1000 ohms. If you are having problems with this component, look for signs of oil or coolant in the connector bay.
2. Injectors
Yesterday accelerating full speed from highway paytoll, I experienced an abrupt drop in power as if the engine was running out of gas or the injectors aren't firing at all. I took out the spark plugs this morning, 3 were soaked in gasoline, and the 4th was dry. I placed a tissue over each hole in the injector and when i start the engine with no sparks, the 3 with gazoline jump out. The 4th one stays closed. I tried to test the ground connections of ECU pins 14,30 and 48/55. I found 0ohm. So i assume the problem is in another place.
I also tried to reset the PID 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 persists at higher RPM. The coolant sensor (G62) even if it is not plugged in, shows a temperature of -49c. I also noticed that the oil pressure gauge in the cockpit shows 2 bar while the actual pressure is 0.0 when I crank up the engine.
I'm not sure what to do. I believe that I've ruled everything else out. I'm concerned that i may have missed something. If anyone has any suggestions, please let me know! TIA!
3. Fuel Pump
The fuel pump in the g28 is activated by a signal from the RPM sensor. The GM-style sender is the same as the G4 and they both work 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. It is simple to test them: simply switch your DMM into resistance mode and test the distance between pins 1 and 2 (with the bump on the connector's edge facing upwards). They should be infinite ohms.
4. ECU
Our 20vt turbo (3B AAN, ABY and ADU) engines have an ECU that needs to be aware of the speed and position of the crankshaft to make a decision about timing of the fuel injectors, etc. To do this, it utilizes a Crank Position Sensor (G4) and an Engine Speed Sensor (G28). If you have a problem with either of these sensors, the diagnostic scanner will show the codes that could trigger the engine shutting down.
A failing G28 sensor can cause an inaccurate gearbox speed counter, a gearbox that shifts more quickly than normal, or an unfire when in the gear. If you experience any of these issues it is likely that your sensor is going bad and needs replacing. They are cheap and easy-to-find particularly when they're an Bosch unit like ours. Alternatively, the GM version of this unit is also a good option.
5. Tachometer
A malfunctioning engine sensor can cause a variety of issues in your car. It is an important part of the transmission of your Audi Q7 Replacement Key, as it transmits information to the ECU on how fast or slowly the engine cost of audi key replacement the car is turning. When this sensor fails, it can cause problems for the transmission, as well as the other car's components.
The G5 engine sensor is located at the edge of the transmission, just above the flywheel ring. It transmits an electrical signal through gray wire to ECU pin T55/49. The ECU utilizes this signal to regulate the amount of fuel and boost, and also timig. It also relays it to the G5 Tachometer in instrument cluster. You can test for sensor failure by checking continuity from the sensor to the tachometer. Also, you can verify continuity between pin T55/49 of the ECU and pin T6a/1 of the instrument cluster (trace [79]), and between pin T6a/1 and pin T26a/12. There should be the resistance to be around 1000 ohms between these two points. This part is common across the audi q5 key 80-100-200-RS2 range, from the 1985 MC all the way up to the 1997 UrS AN and 1995 RS2 Du, so you might find some good ones in wrecking yards.