It could be due to various causes, from something like a loose fender inner shield which maybe rubbing against your tyre or even worn out steering joints
If it is the brakes you are referring to then master cylinder is the main brake unit which is connected to your brake pedal. Calipers or wheel cylinders come on each wheel and are slave units. Same applies for manual transmission vehicles with clutch master and slave cylinders.
What sort of codes or warning lights are there on your 911? Clearing a fault code does not usually take more than an hour unless there is a hard fault registered in the ECU.
If so "what is causing the code" will need to be fixed first. Since it is at the dealership they should be able to update you in a day or two about the car's status. So the best is to call and speak to your service advisor.
What year model is your A4? There is a fuel vapour vent system in the form of a charcoal canister which collects the fuel vapour. There might be a block in the system. Hence when you try to fill fuel, the air in the tank gets purged back to the filling neck causing the fuel filling spout to shut. So the gas station attendant would need to fill it manually.
Your Audi would be making the high pitch noise most likely due to a faulty PCV valve or a vacuum leak. If it is out of warranty I would be able to check it out.
On an average you would be looking at having them changed every 30k. Again it depends on the kind of terrain and driving style. People living in communities with lot of speed humps might see them off even at 20k.
Most likely the bowden cable which is held by the catch on the inner handle has fallen off its slot. You will get a true picture only once the door pad is opened.
If you are already having a noise then the CV joint has run dry and is damaged. Most likely you would be having vibration under acceleration. So you are better off changing the drive shaft rather than fixing the boot.
This is a very common issue due to a faulty brake light switch. Capital Auto (recommended by vwaudiclubuae) in Al Quoz can check out the fault for you.
Is it a p38 or a later model range rover? When was the last time spark plugs were changed? If there are misfire fault codes on specific cylinders then try swapping ignition coils / plug wires to see if the misfire shifts.
There is no dipstick on the LR4 or for that matter on any new age cars to check your transmission level. No transmission fluid is filled for life. Lifetime generally refers
to the life of the vehicle warranty.
It is just that you have extended changing intervals. To keep the tranny in good condition, considering the extreme weather, it would be ideal to have it
renewed every 100k.