its an electric system on this car with a motor on the steering column
for it to suddenly stop working then either there's a lack of power to the steering control module or the module has developed a fault
as you already have the dealer lined up to look at it then there's not much else you can do other than check the power steering fuses and the main connections to the module under the dash
if you locate the motor on the column 1st and then trace the wiring back to the control module from there
do you still need help?
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