Manufacturer communication · Service bulletin · 4 brands

GM bulletin PIT6425B

What it saysThis Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC's NHTSA’s full summary ↓

GM filed this with NHTSA as a service bulletin dated Oct 18, 2025, received Oct 24, 2025. It names 337 model years across Chevrolet, GMC, Buick and Cadillac (2019–2027). 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 · Buick · Cadillac.

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ModelEmail address

What the bulletin says

Source: NHTSA's summary of the manufacturer's communication

This Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC's

Trouble codes it names: U0411 all 1 read from the document itself; NHTSA’s summary names none

Kind Service bulletin Manufacturer date Oct 18, 2025 Received by NHTSA Oct 24, 2025 Components —

Document filed under this number

Document	Kind	Dated	NHTSA id	At NHTSA
PIT6425B	Service bulletin	Oct 18, 2025	11024460	PDF, 112 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.

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Model years it names

Source: as the manufacturer filed them

Chevrolet 173 model years

Also filed against model years this site has no page for: 2024 Chevrolet 3500HD; 2019 Chevrolet 4500; 2020 Chevrolet 4500; 2022 Chevrolet 4500; 2019 Chevrolet 4500HD; 2020 Chevrolet 4500HD; 2021 Chevrolet 4500HD; 2022 Chevrolet 4500HD; 2023 Chevrolet 4500HD; 2019 Chevrolet 4500XD; 2020 Chevrolet 4500XD; 2021 Chevrolet 4500XD; 2022 Chevrolet 4500XD; 2019 Chevrolet 5500HD; 2020 Chevrolet 5500HD; 2021 Chevrolet 5500HD; 2022 Chevrolet 5500HD; 2023 Chevrolet 5500HD; 2019 Chevrolet 5500XD; 2020 Chevrolet 5500XD; 2021 Chevrolet 5500XD; 2022 Chevrolet 5500XD; 2019 Chevrolet 6500; 2019 Chevrolet 6500HD; 2020 Chevrolet 6500HD; 2021 Chevrolet 6500HD; 2022 Chevrolet 6500HD; 2023 Chevrolet 6500HD; 2024 Chevrolet Bolt EV; 2025 Chevrolet Brightdrop 400; 2026 Chevrolet Brightdrop 400; 2025 Chevrolet Brightdrop 600; 2026 Chevrolet Brightdrop 600; 2019 Chevrolet LOW Cab Forward 3500; 2026 Chevrolet LOW Cab Forward 3500; 2026 Chevrolet LOW Cab Forward 5500; 2026 Chevrolet LOW Cab Forward 6500; 2025 Chevrolet LOW Cab Forward N Series; 2019 Chevrolet Trailblazer; 2020 Chevrolet Trailblazer; 2023 Chevrolet Trax.

GMC 71 model years

2026 GMC Acadia 2025 GMC Acadia 2024 GMC Acadia 2023 GMC Acadia 2022 GMC Acadia 2021 GMC Acadia 2020 GMC Acadia 2019 GMC Acadia

Also filed against model years this site has no page for: 2024 GMC 3500HD; 2022 GMC Hummer EV Pickup; 2026 GMC Hummer EV Pickup; 2026 GMC Hummer EV SUV.

Buick 32 model years

2019 Buick Cascada 2026 Buick Enclave 2025 Buick Enclave 2024 Buick Enclave 2023 Buick Enclave 2022 Buick Enclave 2021 Buick Enclave 2020 Buick Enclave

and 23 more on this site: 2019 Buick Enclave, 2026 Buick Encore, 2025 Buick Encore, 2024 Buick Encore, 2023 Buick Encore, 2022 Buick Encore, 2021 Buick Encore, 2020 Buick Encore, 2019 Buick Encore, 2026 Buick Envision, 2025 Buick Envision, 2024 Buick Envision, 2023 Buick Envision, 2022 Buick Envision, 2021 Buick Envision, 2020 Buick Envision, 2019 Buick Envision, 2026 Buick Envista, 2025 Buick Envista, 2024 Buick Envista, 2019 Buick LaCrosse, 2020 Buick Regal, 2019 Buick Regal.

Also filed against model years this site has no page for: 2020 Buick Lacrosse.

Cadillac 61 model years

2019 Cadillac ATS 2026 Cadillac CT4 2025 Cadillac CT4 2024 Cadillac CT4 2023 Cadillac CT4 2022 Cadillac CT4 2021 Cadillac CT4 2020 Cadillac CT4

Also filed against model years this site has no page for: 2021 Cadillac CT6; 2026 Cadillac XT4; 2026 Cadillac XT6; 2020 Cadillac XTS.

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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ModelEmail address

What owners reported

Source: NHTSA complaint database

Owners of the 287 model years this bulletin names have filed 25,156 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, Buick and Cadillac, by the number printed on the letter.

Every Chevrolet bulletin →Look up another number

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Common questions

Source: NHTSA, 49 CFR 579.5

Is GM PIT6425B 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 PIT6425B 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. Every GM warranty extension on file lists the ones GM has filed.

Which vehicles does PIT6425B cover?

The manufacturer filed it against 337 model years across 4 brands (Chevrolet, GMC, Buick and Cadillac): 2019 Buick Cascada, 2026 Buick Enclave, 2025 Buick Enclave, 2024 Buick Enclave, 2023 Buick Enclave, 2022 Buick Enclave and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.

From here

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