need help 2001 A8L wont start ,, hellp please
 

hey guys,

i got a 2001 A8L .. which just recently today it wont start.. it keeps cranking and cranking but it wont turn over.. ran the codes and got p0301 and p0321. please help.. does it have to do anything with the crankshaft position sensor?? if so where is the sensor located ( any pictures of the location) and how hard is to replace.. any steps or procedures would be appreciated. thanks