Cadillac Deville 2002–2003 — technical service bulletin
Bulletin 030604028 · NHTSA communication 10002446 · issued May 1, 2003
Technical service bulletin
communication type
Engine and Engine Cooling
component
2002–2003
model years
4
vehicle entries
Official summary
Service engine soon (ses) light on, reduced vehicle power / acceleration / speed, diagnostic trouble code (dtc) p0420. *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.