Exactly, what should be a swan dance on ice looks like wrestling the ESP when it tries to interfere.. There is a way to fool it around, especially when you do not countersteer under heavy load sideways, so all 4 wheels spin and it has no way of telling you are sliding.. but once you try to correct your course with a steering wheel, it suffers. I had a ESP failure message come up several times (shuts up when I restart the car)....
to answer your question, yes, I experienced a fully disabled ESP when I engaged the ESP system function test and I could not wash the smile off my face for quite a while after that
. Fortunately, I had an empty snow covered meadow at my disposal, so I could test and try all I wanted. I cannot say it felt safe, since this car has an especially poor lateral traction even without ESP being off, due to poor weight distribution, high centre of gravity (which I hope to ameliorate by Eibach springs and Bilstein shocks), high weight and the Haldex system functioning itself
so I strongly recommend you try it first on an empty and sufficiently spacious parking lot to get the idea, because the car really slides sideways more than one might expect.. btw, I run this test accidentally, when trying to find a way to disable ESP, and found out how I did it only after a consultation with EBD11 technical support
it worked nevertheless.
To complete the test, you need to follow this procedure:
Accelerate in a straight line up to around 20km/h
Then turn the steering wheel left or right at least 90 degrees (but no more than 180 degrees) while maintaining the speed
Otherwise, the ESP will remain fully OFF (only when turned off with an ESP button), and you will see a fault code 01486 in the Brake unit computer. I did not follow this procedure and it took a few days for the test to turn off by itself, either by completing the procedure unwittingly (possibly when I was parking a car somewhere), or the test just terminated after certain period of time, I am not sure.
Let me know how it worked for you.. And how much fun you had