{"nhtsa_id":11035141,"type":"warranty_extension","type_name":"Warranty extension","date_added":"2026-07-21","date":"2026-07-13","document_id":"26-01-052H TSB","mfr_campaign":"LA30","replaces":null,"component":"ELECTRICAL SYSTEM","mfr_system":null,"summary":"Certain Sonata Hybrid (DN8 HEV) vehicles may exhibit intermittent battery discharge conditions due to the air conditioning controller not fully powering down after the vehicle is turned off and parked. This bulletin provides the procedure to update the Air Temperature Control Unit (ATCU) 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.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035141-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035141-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11035141","components":[{"id":"electrical","name":"Electrical system","parent":null}],"codes":[],"topics":[],"vehicles":[{"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":[]}