20 Most Recent 2009 Audi A6 Avant - Page 3 Questions & Answers

Boy you had better go back and read more about what a catalytic converter does, remember in chemistry a catalyst is a thing that facilitates a chemical reaction but is not directly involved in that reaction? Ring a bell.

if you have had all them parts changed and its binding one moment then not working correct. the possible problem can be the abs unit, when you apply the brakes the abs controls the pressure. if the vale in the abs unit is faulty you can get this problem and worse. you may not even get a code as the coil is still fine is just its stuck. i would have this part checked or replaced.

Cannot fathom what an icu has to do with brakes. Hydraulics control braking effort and effectiveness. Car should stop unless you are lacking brake fluid or have issues with master cylinder. Computer gets involved when you have anti lock brakes, etc.

Fan turns on when you turn the AC on, and when coolant gets too hot (over middle of the instrument). White smoke in exhaust means coolant gets into the cylinder, typically head gasket or crack. Is the upper radiator hose (the one that goes to the coolant expansion tank getting very hot? Observe when car is warming up. When coolant temp gauge needle is in the middle, the upper radiator hose should get warm; also the radiator (you can touch the top and check) should get warm at that time. The means that the thermostat opened as it should (when engine warmed up). If it does NOT get hot, then the thermostat is stuck closed, which can lead to overheating. Still, the fans should kick in.