GM bulletin 25-NA-121
What it saysThis service bulletin provides information on the radio software related issues to update the radio to the latest software version Y177. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated May 13, 2025, received Oct 27, 2025, about the electrical system. It names 6 model years across Chevrolet and GMC (2025). 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.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis service bulletin provides information on the radio software related issues to update the radio to the latest software version Y177.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 25-NA-121 | Service bulletin | May 13, 2025 | 11024501 | PDF, 840 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 3 model years
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 325 complaints with NHTSA since 2015. 72 of them name Electrical System — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
The vehicle experienced repeated high-voltage system warnings and battery conditioning system failures. On multiple occasions the “Service High Voltage System” message appeared along with codes P0530 and P1C26 related to the lithium-ion battery conditioning system that controls heating and cooling of the high-voltage battery pack.
2025 Chevrolet Silverado · Electrical System · filed with NHTSA Jul 15, 2026
The infotainment system regularly stops producing audio. This applies to all audio, including turn signal, navigation, radio and Apple Carplay. Yes, it's available to inspection. While it's not a huge safety concern, there have been a couple times it's quite working, and I was very distracted by the audio cutting in and out.
2025 Chevrolet Silverado 3500HD · Electrical System · filed with NHTSA May 18, 2026
Radio does not emit sound also canceling all warning noises for fuel level, turn signals, seat belts, open door in motion. This problem is not only a saftey hazard for drivers its a major annoyance. Honestly find it quite distracting. Have reached out to gm multiple times and the issue hasn't been corrected.
2025 Chevrolet Silverado 2500HD · Electrical System · filed with NHTSA Jul 22, 2026
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.
More bulletins about the electrical system
Source: same model, same component group252 other manufacturer communications filed against these GM models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N252529080 | Service campaign | Apr 1, 2026 | Service Update. Certain vehicles listed above may be missing a high voltage header plug on the RESS battery pack drive motor connector. Dea… |
| N252515590 | Service campaign | Jan 27, 2026 | Certain vehicles listed above, may have a condition in which the body-to-chassis ground strap may be corroded. Dealers will replace the grou… |
| 18-NA-180 | Service bulletin | Sep 4, 2025 | This Warranty Administration service bulletin provides Lithium-Ion battery Exchange Process and Transaction Submission information. |
| 22-NA-083 | Service bulletin | May 17, 2025 | This service bulletin provides Requirements for Replacement of the Dual Mode Cord Set Under Warranty. |
| 23-NA-151 | Service bulletin | May 16, 2025 | This service bulletin and criteria within are to determine the internal state of the High Voltage Battery and core return shipping method. |
| PIE0753I | Service bulletin | May 15, 2025 | This engineering information (EI) will assist GM to recover a small number of electric vehicle battery packs from customer-owned vehicles in… |
| 25-NA-044 | Service bulletin | May 14, 2025 | This service bulletin provides information for dealers/technicians on SPS2 Hybrid/EV Battery Data Retrieval for Service High Voltage DTCs. |
| 24-NA-202 | Service bulletin | May 14, 2025 | This service bulletin provides dealers with Warranty Administration information on North American Charging Standard (NACS) DC Adapter Warran… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet and GMC, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 25-NA-121 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 25-NA-121 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 25-NA-121 cover?
The manufacturer filed it against 6 model years across 2 brands (Chevrolet and GMC): 2025 Chevrolet Silverado, 2025 Chevrolet Silverado 2500HD, 2025 Chevrolet Silverado 3500HD, 2025 GMC Sierra, 2025 GMC Sierra 2500HD, 2025 GMC Sierra 3500HD. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.