Generations

Engine Codes

 * APB (1998-2001) - North American S4
 * ASJ (2000?) - RS4 F-box
 * AZR (2001?-2003) - RS4 Q/K-box


 * AGB (1997-2001?) - European S4 C/D-box, No post cat O2 sensors, Bosch MAF, original intake manifold
 * AZB (2001?) - European S4 G/N/P-box


 * APB (?-2002) - Allroad/A6 ./X/L-box
 * BEL (2003-?) - Allroad/A6 R/MX/S/T-box

OEM equipment

 * Note: The build date cutoff for 2001 to 2001.5 is inconsistent and sometimes arbitrary. Both '01 and '01.5 cars have been reported as 09/00 build.
 * Note: Manufacturer Year is inconsistent and sometimes arbitrary. See Notes below.
 * Note: It is a common misconception that 2001.5 introduced updated oil lines. There is no conclusive evidence of this.

North American Production numbers
2002 is build date of 06/01 to 07/01