Audi A4 2000–2001 — technical service bulletin
Bulletin 0504 · NHTSA communication 10015999 · issued Jul 20, 2005
Technical service bulletin
communication type
Engine and Engine Cooling
component
2000–2001
model years
4
vehicle entries
Official summary
Three way catalyst, catalytic efficiency diagnostic trouble codes (dtcs) stored in dtc memory. *tt
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.