{"nhtsa_id":11035142,"type":"warranty_extension","type_name":"Warranty extension","date_added":"2026-07-21","date":"2026-07-14","document_id":"LA29-LA30 DCS","mfr_campaign":"LA29 / LA30","replaces":null,"component":"ELECTRICAL SYSTEM","mfr_system":null,"summary":"Certain 2024-2026MY Sonata (DN8) and 2024-2026MY Sonata Hybrid (DN8 HEV) vehicles may exhibit intermittent battery discharge condition due to the air conditioning controller not fully powering down after the vehicle is turned off and parked. Technical Service Bulletins (TSB) 26-01-051H & 26-01-052H provide the procedure to update the ATCU (Air Temperature Control Unit) software; the revised logic improves controller shutdown to prevent battery drain and corrects a condition where the HVAC control display may appear blank when climate remote start is activated via Bluelink. Over-the-Air (OTA): This update can also be conducted via OTA. Customers can complete on their own if they have an active subscription to Hyundai Bluelink. A visit to the dealership is not required. Deployment of the OTA to Bluelink customers is planned to start the week of 07/13/26.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035142-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035142-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11035142","components":[{"id":"electrical","name":"Electrical system","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"HYUNDAI","model":"SONATA","year_from":2024,"year_to":2026,"match":"exact","vehicle_ids":["2024_hyundai_sonata","2025_hyundai_sonata","2026_hyundai_sonata"]},{"make":"HYUNDAI","model":"SONATA HYBRID","year_from":2024,"year_to":2026,"match":"base","vehicle_ids":["2024_hyundai_sonata","2025_hyundai_sonata","2026_hyundai_sonata"]}],"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":[]}