GM bulletin PIT6450A
What it saysThis preliminary information communicates an issue with a Service Brake system message and DTC C0597 C055F. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Nov 14, 2025, received Nov 18, 2025. It names 6 model years across Chevrolet, GMC and Cadillac (2026). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
One page for every brand it was filed under. Each brand’s bulletins: Chevrolet · GMC · Cadillac.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationPicked out of NHTSA’s summary below, word for word. The document itself is the record, and the dealer checks the VIN.
This preliminary information communicates an issue with a Service Brake system message and DTC C0597 C055F. Dealers are to replace the brake master cylinder.
Trouble codes it names: C055F C0597
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| PIT6450A | Service bulletin | Nov 14, 2025 | 11025584 | PDF, 109 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themChevrolet 3 model years
GMC 2 model years
Cadillac 1 model year
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 6 model years this bulletin names have filed 407 complaints with NHTSA since 2015.
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet, GMC and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM PIT6450A a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the PIT6450A repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way.
Which vehicles does PIT6450A cover?
The manufacturer filed it against 6 model years across 3 brands (Chevrolet, GMC and Cadillac): 2026 Cadillac Escalade, 2026 Chevrolet Silverado, 2026 Chevrolet Suburban, 2026 Chevrolet Tahoe, 2026 GMC Sierra, 2026 GMC Yukon. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.