Brightdrop EV600 2020–2026 — technical service bulletin
Bulletin PIT6401 · NHTSA communication 11019846 · issued Jun 19, 2025
Technical service bulletin
communication type
Unknown OR Other
component
2020–2026
model years
60
vehicle entries
Official summary
This Preliminary information communicates a diagnostic tip on how to resolve a issue of the horn sounding when vehicle doors are being closed and the key in vehicle reminder set to off.
Vehicles covered
- 2022 Brightdrop EV600
- 2024 Brightdrop Zevo 400
- 2023 Brightdrop Zevo 600
- 2024 Brightdrop Zevo 600
- 2021 Buick Envision
- 2022 Buick Envision
- 2023 Buick Envision
- 2024 Buick Envision
- 2025 Buick Envision
- 2026 Buick Envision
- 2020 Cadillac CT4
- 2021 Cadillac CT4
- 2022 Cadillac CT4
- 2023 Cadillac CT4
- 2024 Cadillac CT4
- 2025 Cadillac CT4
- 2026 Cadillac CT4
- 2020 Cadillac CT5
- 2021 Cadillac CT5
- 2022 Cadillac CT5
- 2023 Cadillac CT5
- 2024 Cadillac CT5
- 2025 Cadillac CT5
- 2026 Cadillac CT5
- 2021 Cadillac Escalade
- 2022 Cadillac Escalade
- 2023 Cadillac Escalade
- 2024 Cadillac Escalade
- 2025 Cadillac Escalade
- 2026 Cadillac Escalade
- 2025 Cadillac Escalade Esv
- 2026 Cadillac Escalade Esv
- 2025 Cadillac Escalade IQ
- 2026 Cadillac Escalade IQ
- 2023 Cadillac Lyriq
- 2024 Cadillac Lyriq
- 2025 Cadillac Lyriq
- 2026 Cadillac Lyriq
- 2025 Cadillac Optiq
- 2026 Cadillac Optiq
- 2026 Cadillac Vistiq
- 2024 Cadillac XT4
- 2025 Cadillac XT4
- 2024 Chevrolet Blazer EV
- 2025 Chevrolet Blazer EV
- 2025 Chevrolet Brightdrop 400
- 2026 Chevrolet Brightdrop 400
- 2025 Chevrolet Brightdrop 600
- 2026 Chevrolet Brightdrop 600
- 2023 Chevrolet Colorado
- 2024 Chevrolet Colorado
- 2025 Chevrolet Colorado
- 2026 Chevrolet Colorado
- 2025 Chevrolet Equinox
- 2026 Chevrolet Equinox
- 2024 Chevrolet Equinox EV
- 2025 Chevrolet Equinox EV
- 2022 Chevrolet Silverado 1500
- 2023 Chevrolet Silverado 1500
- 2024 Chevrolet Silverado 1500
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.