Mazda Millenia 1997–2000 — technical service bulletin
Bulletin 0100301 · NHTSA communication 620007 · issued Feb 28, 2001
Technical service bulletin
communication type
Unknown OR Other
component
1997–2000
model years
4
vehicle entries
Official summary
Some vehicles may exhibit malfunction indicator lamp illumination with diagnostic trouble code (dtc) p0420 / 0421 or p0430 / 0431 stored in memory with no driveability concerns present. This condition may be caused by an overly sensitive rear oxygen sensor(s), which fasely indicates an emissions concern and a dtc to be stored. *tt
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.