{"nhtsa_id":10004367,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2003-12-04","date":"2003-08-01","document_id":"030421006","mfr_campaign":null,"replaces":null,"component":"POWER TRAIN:TRANSFER CASE (4-WHEEL DRIVE)","mfr_system":null,"summary":"SERVICE 4WD LIGHT ON, 4WD INOPERATIVE, HARSH ENGAGEMENT OF 4WD, NO COMMUNICATION WITH TRANSFER CASE CONTROL MODULE (TCCM), TCCM DIAGNOSTIC TROUBLE CODE (DTC) C0550 SET. *TT","document":null,"url":"https://open.wenmarpro.com/bulletins/10004367","components":[{"id":"powertrain","name":"Transmission and driveline","parent":null},{"id":"transfer-case","name":"Transfer case","parent":"powertrain"}],"codes":["C0550"],"topics":[],"vehicles":[{"make":"BUICK","model":"RAINIER","year_from":2004,"year_to":2004,"match":"exact","vehicle_ids":["2004_buick_rainier"]},{"make":"CHEVROLET","model":"TRAILBLAZER","year_from":2004,"year_to":2004,"match":"exact","vehicle_ids":["2004_chevrolet_trailblazer"]},{"make":"GMC","model":"ENVOY","year_from":2004,"year_to":2004,"match":"exact","vehicle_ids":["2004_gmc_envoy"]},{"make":"OLDSMOBILE","model":"BRAVADA","year_from":2004,"year_to":2004,"match":"exact","vehicle_ids":["2004_oldsmobile_bravada"]}],"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":[]}