Chevrolet Avalanche 2003 — technical service bulletin
Bulletin 030421001C · NHTSA communication 10002856 · issued Jun 1, 2003
Technical service bulletin
communication type
Power Train
component
2003
model years
6
vehicle entries
Official summary
4-wheel drive switch indicator lights flashing, 4-wheel drive inoperative, diagnostic trouble codes c0327, p0836, p0500. *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.