TSB 662.11 — Buick, Chevrolet and GMC Software update
662.11 is a software update on file with NHTSA for 4 Buick, Chevrolet and GMC models, 2024–2026 model years, filed and re-filed as 2 documents. A TSB is factory repair guidance, not a recall — the repair is not automatically free.
What the bulletin says. • Fixes to help ensure proper functionality for shifting. • Fixes to help protect transmission health. • Improvements to diagnostics to prevent vehicle not starting. • Fixes to help reduce instances of check engine light activation in cold weather.
NHTSA's own summary of the document, quoted from the public manufacturer-communications file.
Worth checking your VIN against. 662.11 is filed as a software update, which unlike an ordinary bulletin can mean free or reimbursed work when a vehicle qualifies. Ask a dealer using the document ID below, and check open recalls separately at nhtsa.gov/recalls.
Vehicles and model years 662.11 names
| Vehicle | Model years |
|---|---|
| Buick Enclave | 2024, 2025 |
| Chevrolet Silverado 2500 | 2026 |
| Chevrolet Traverse | 2024, 2025 |
| GMC Acadia | 2024, 2025 |
Every document filed under 662.11
Manufacturers re-issue a bulletin as the repair changes, and file separate copies for technicians and for owners. All of them carry the same number.
| Document ID | Filed | Type |
|---|---|---|
| 662.11 | July 23, 2026 | Software update |
| 662.11 | July 14, 2026 | Software update |
Questions buyers ask
What is TSB 662.11?
662.11 is a software update filed with NHTSA by Buick, Chevrolet and GMC, covering 4 Buick, Chevrolet and GMC models across the 2024–2026 model years. NHTSA's summary reads: • Fixes to help ensure proper functionality for shifting. • Fixes to help protect transmission health. • Improvements to diagnostics to prevent vehicle not starting. • Fixes to help reduce instances of check engine light activation in cold weather.
Which vehicles does 662.11 cover?
NHTSA's file names Buick Enclave (2024–2025); Chevrolet Silverado 2500 (2026); Chevrolet Traverse (2024–2025); GMC Acadia (2024–2025). A bulletin number can be re-issued against more vehicles later, so check the model-year list on this page against your own.
Is TSB 662.11 a recall, and is the repair free?
662.11 is filed as a software update, not a recall — but this is the kind of communication that can mean free or reimbursed work if your VIN qualifies. Take the number to a dealer and ask. Recalls are separate and always free; check yours by VIN at nhtsa.gov/recalls.
How do I get the full text of 662.11?
Take the document ID to a dealer's service desk, or search NHTSA's manufacturer-communications records. This page carries every document ID filed under 662.11, its date, and NHTSA's own summary from the public file.
Every number on this page is a count of records in the federal complaint, recall, and investigation files published by NHTSA's Office of Defects Investigation. This page lists only what NHTSA's manufacturer-communications file records under 662.11. Check any specific vehicle's open recalls by VIN at nhtsa.gov/recalls.