Chevrolet Silverado 2005 — technical service bulletin
Bulletin 612 · NHTSA communication 10015784 · issued Dec 1, 2004
Technical service bulletin
communication type
Service Brakes, Hydraulic
component
2005
model years
2
vehicle entries
Official summary
Service engine soon light illuminated. Diagnostic trouble code (dtc) p0171 and/or p0174 (lean fuel trim) may be set. Master cylinder o-ring damaged. Gm tech link. *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.