{"nhtsa_id":11025925,"type":"over_the_air","type_name":"Over-the-air update","date_added":"2025-12-02","date":"2025-11-25","document_id":"653.21","mfr_campaign":"653.21","replaces":null,"component":"UNKNOWN OR OTHER","mfr_system":"BCM, TCP: BCM (Body Control Module), TCP (Telematics Communication Platform)","summary":"GM Update 653.21 • Improves how center display adjusts to lighting changes. • Improved warnings when a key is missing. • Better tuning for interior lighting in Stealth mode. • Improvements to automatic low beam headlamp logic. • Smoother dimming and transitions from day to night. • Fixes to help prevent battery drain. • Fixes to responsiveness issues with Wi-Fi, Navigation, Super Cruise, and OnStar. • Improvements to software updates. • Improvements to OnStar emergency calls. • Fixes to address cellular connectivity issues. During the update process, your radio may stay on up to 5 minutes after you exit the vehicle. This is expected behavior when an update package is onboard the vehicle. Do not service your vehicle during installation.","document":{"url":"https://static.nhtsa.gov/odi/tsbs/2025/MC-11025925-0001.pdf","alternate_url":"https://static.nhtsa.gov/odi/tsbs/2025/MC-11025925-9999.pdf","confirmed":false},"url":"https://open.wenmarpro.com/bulletins/11025925","components":[],"codes":[],"topics":[],"vehicles":[{"make":"CADILLAC","model":"XT4","year_from":2025,"year_to":2025,"match":"exact","vehicle_ids":["2025_cadillac_xt4"]}],"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":[]}