PI 2027 Yukon/Yukon XL B1599 and/or B0126 Setting and Directs to Contact TCSC — PIC6663

[AT4Forum]

Preliminary information · Preliminary information PIC6663

This is a preliminary information note, not a recall. GMC sends these to dealer technicians about a known condition, often while a fix is still being worked out. They are not repair orders, and they don't by themselves change what is covered.

Published: Sep 18, 2026
Applies to: Yukon, Yukon XL (2027 model year)

Summary (official text)​

This PI communicates the possibility of a B1599 and/or B0126 setting and directs to contact TCSC.

Sources​

• PIC6663 (PDF, NHTSA document 11037457) — Sep 18, 2026
• PIC6663A (PDF, NHTSA document 11038586) — Oct 16, 2026

Details from NHTSA as of Oct 22, 2026. If NHTSA or GMC revises this notice, this post is updated and significant changes are noted in a reply. The linked documents are the authority, and a dealer can confirm whether it applies to your VIN.

Have you experienced this issue with your vehicle? Let us know your model year and engine, plus any diagnosis or repair details.

 

AT4 Forum Fav 👍

Sellars Toolbox Shop Towels Dispenser Bucket - Grab one through Amazon!