# Over\-the\-air update 661.21

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: 11031812
- Published by NHTSA: 2026\-04\-30
- Manufacturer's number: 661.21
- Manufacturer's date: 2026\-04\-28
- Campaign id or software version: 661.21
- NHTSA component: UNKNOWN OR OTHER
- Manufacturer's system: CGM, AMP, AOS, EBCM, LRR, FCM, SRR, SBZA: CGM, AMP, AOS, EBCM, LRR, FCM, SRR, SBZA

## NHTSA's summary

• Improvements to interior audio quality and volume consistency. • Improves traction and stability control when accelerating or on uneven terrain. • Improves braking and stopping performance on low\-traction surfaces. • Improvements to the performance of Automatic Emergency Braking and Adaptive Cruise Control braking. • Fixes to help ensure proper functionality of Forward Collision Alert and availability of driver assistance features. • Fixes to help protect battery life. • Improvements to provide more accurate speed limit detection on the driver’s display. • Fixes to help ensure driver assistance features remain functional when the windshield freezes. • Fixes to help ensure accurate driver display messages and alerts.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11031812-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11031812-9999.pdf)

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

## Vehicles listed

- 2024 CADILLAC LYRIQ

JSON: [/v1/bulletins/11031812](/v1/bulletins/11031812)

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