Audi A4 2009–2013 — technical service bulletin
Bulletin 01130120330012 · NHTSA communication 10224985 · issued May 29, 2013
Technical service bulletin
communication type
Engine and Engine Cooling
component
2009–2013
model years
16
vehicle entries
Official summary
Under certain driving conditions, the secondary air ports in the cylinder head can accumulate carbon over time, causing a restriction.
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.