Cadillac bulletin 653.21
Cadillac filed this with NHTSA as a over-the-air update dated Nov 25, 2025, received Dec 2, 2025, about the unknown or other. It names 1 model year (2025). A over-the-air update is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationGM 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 filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 653.21 | Over-the-air update | Nov 25, 2025 | 11025925 | not yet checked |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themA vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
Common questions
Source: NHTSA, 49 CFR 579.5Is Cadillac 653.21 a recall?
No. A over-the-air update is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the 653.21 repair free?
A over-the-air update is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does 653.21 cover?
The manufacturer filed it against 1 model year: 2025 Cadillac XT4. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.