2010 S5 4.2l will not crank
 

. yesterday my s5 stopped starting. It will not even crank not even a solenoid click from the starter. Battery voltage good at 12.3v. All other electrical items seem to function OK, but nothing from the starter. Any Idea on what the cause could be (I understand that the starter motor is difficult to replace, so I am hoping that is not the problem).