It takes Group 48 battery.
its on the lougage compartment
The 2001 Audi A4 Quattro typically uses a 12-volt lead-acid battery, commonly with a group size of 49 or H7. It's essential to check the specifications for the exact model and engine type, as variations may exist. When replacing the battery, ensure it meets the required cold cranking amps (CCA) for optimal performance.
The 2009 Audi A4 has double overhead cam (DOHC).
The 2012 Audi A4 has double overhead cam (DOHC).
The 2005 Audi A4 has double overhead cam (DOHC).
The 2004 Audi A4 has double overhead cam (DOHC).
The 2014 Audi A4 has double overhead cam (DOHC).
The 2007 Audi A4 has double overhead cam (DOHC).
The 2010 Audi A4 has double overhead cam (DOHC).
The 2003 Audi A4 has double overhead cam (DOHC).
The 2013 Audi A4 has double overhead cam (DOHC).
The 2011 Audi A4 has double overhead cam (DOHC).