Over-the-air update 662.21
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.
| Type | Over-the-air update |
|---|---|
| NHTSA id | 11036471 |
| Published by NHTSA | 2026-08-31 |
| Manufacturer's number | 662.21 |
| Manufacturer's date | 2026-08-05 |
| Campaign id or software version | 662.21 |
| NHTSA component | UNKNOWN OR OTHER |
| Manufacturer's system | BCM, TCM, ECM: BCM (Body Control Module), TCM (Transmission Control Module), ECM (Engine Control Module) |
NHTSA's summary
• Fixes to help ensure proper functionality for heating and cooling features. • Improvements to night mode lights for shifting gears. • Fixes for Daytime Running Lamps turning on when set to Off. • Fixes to help prevent erroneous missing key messages on driver display. • Fixes for accuracy of low tire pressure alert. • Fixes for speed threshold for pedestrian alerts. • Improvements to start reliability and reduced check engine light activation • Improvements to turbo system diagnostics • Improvements to reliability when extending the running boards on your vehicle • Improves transmission diagnostic software. • Reduces unnecessary check engine light activations. • Fixes to help extend coolant valve life through diagnostic changes
The document
The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.
| CHEVROLET SILVERADO 1500 | 2025 (the catalog's model; the bulletin names a series or trim of it) |
|---|---|
| GMC SIERRA 1500 | 2025 (the catalog's model; the bulletin names a series or trim of it) |
Listing a model year does not mean every vehicle of it is concerned: the document says which.