{"nhtsa_id":634977,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2002-10-11","date":"2002-06-01","document_id":"020941001","mfr_campaign":null,"replaces":"990603010A","component":"UNKNOWN OR OTHER","mfr_system":null,"summary":"DIAGNOSTIC TROUBLE CODES B1001, B1271 OR B1780 SET WHEN REPLACING / REPROGRAMMING OTHER MODULES FOR 1999 - 2003 PASSENGER CARS AND TRUCKS WITH CLASS 2 SERIAL DATA COMMUNICATION BETWEEN MODULES. *TT","document":null,"url":"https://open.wenmarpro.com/bulletins/634977","components":[],"codes":["B1001","B1271","B1780"],"topics":[],"vehicles":[{"make":"AM GENERAL","model":"HUMMER","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"BUICK","model":"BUICK","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"CADILLAC","model":"CADILLAC","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"CHEVROLET","model":"CHEVROLET","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"GMC","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"OLDSMOBILE","model":"OLDSMOBILE","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]},{"make":"PONTIAC","model":"PONTIAC","year_from":null,"year_to":null,"match":null,"vehicle_ids":[]}],"as_of":"2026-10-19","note":"A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.","attribution":[]}