So i purchased a 2nd hand car in birmingham a audi a6 ive had a local mech shop tell me the only issue they can find is a adblue blockage, the car keeps limping, he said they dont deal with adblue but i have to take it to the local audi mechs so i have done this they now want to run they own diagnostics at £220 no issue to be told the same thing when this issue is resolved will the car still go into limp mode if its the only isse the car has? new to audi cars all together never knew what adblue was for till i researched it was not even told the car needed it till i saw it by the deisal cap lol can anyone help please