Service bulletins for the 2021 Cadillac CT4
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.
813 on file from NHTSA, as of 2026-10-19.
By type
By component
By trouble code
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Only bulletins with component: Headlights are shown. Show all
| 21NA137 | 2021-08-09. Service bulletin. EXTERIOR LIGHTING:HEADLIGHTS. This service bulletin provides information for dealers/technicians on headlamp beam shadow appearance, and/or driver side to passenger side beam appears unlevel. |
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The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.