# Over\-the\-air update 661.20

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: 11034066
- Published by NHTSA: 2026\-06\-26
- Manufacturer's number: 661.20
- Manufacturer's date: 2026\-06\-18
- Campaign id or software version: 661.20
- NHTSA component: UNKNOWN OR OTHER
- Manufacturer's system: BCM, EBCM: BCM \(Body Control Module\), EBCM \(Electronic Brake Control Module\)

## NHTSA's summary

• Improves traction and stability control when accelerating or on uneven terrain. • Improves braking and stopping performance on low\-traction surfaces. • Improves the performance of assisted braking features. • The active cabin ventilation feature will operate more reliably. • Additional protection for the health of your battery and updates to help prevent excessive battery drain and overheating. • Improvements will support successful software updates for your vehicle and allow you to access new features and fixes.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11034066-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11034066-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Vehicles listed

- 2025 CADILLAC CT4
- 2025 CADILLAC CT5

JSON: [/v1/bulletins/11034066](/v1/bulletins/11034066)

[Report an error on this page](https://github.com/wenmar-pro/wenmar-open/issues/new?template=data_correction.yml&title=Data%20correction%3A%20Over-the-air%20update%20661.20&page=https%3A%2F%2Fopen.wenmarpro.com%2Fbulletins%2F11034066&vehicle=Over-the-air%20update%20661.20)