{"nhtsa_id":11035140,"type":"warranty_extension","type_name":"Warranty extension","date_added":"2026-07-21","date":"2026-07-13","document_id":"7/13/2026 TSB","mfr_campaign":"LA29","replaces":null,"component":"ELECTRICAL SYSTEM","mfr_system":null,"summary":"Certain Sonata (DN8) 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. This bulletin provides 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.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035140-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2026/MC-11035140-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11035140","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"]}],"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":[]}