GM bulletin PIC6551
What it saysThis Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Aug 13, 2024, about the electrical system. It names 54 model years across Chevrolet, GMC, Buick and Cadillac (2021–2022). 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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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| PIC6551 | Service bulletin | Aug 13, 2024 | 11006283 | PDF, 90 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 26 model years
GMC 12 model years
Buick 6 model years
Cadillac 10 model years
and 2 more on this site: 2022 Cadillac XT6, 2021 Cadillac XT6.
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 54 model years this bulletin names have filed 7,155 complaints with NHTSA since 2015. 1,219 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.
On the 2021 GMC Sierra, the 17 owners who gave an odometer reading for Electrical System reported it at a median of 23,300 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
There are crackling sounds coming from the wheel when going over humps. no power while driving or changing lanes it's worst when the ac is on, was burning gas like crazy, and shakes at 65 mph., the gas while escalating makes a clicking noise like 2 iron knocking together, and the dashboard including the radio, and telephone screens goes…
2021 Chevrolet Colorado · Electrical System · filed with NHTSA Jul 25, 2023 · ODI 11534435
On September 15,2026, my vehicle experienced a catastrophic los of power steering assist accompanied by severe heavy steering. Please review General Motors TSB 20-NA-215 & TSB 17-NA-158 both addressing this issue. My 2021 vehicle has a build date of September 19, 2020 which falls "directly" in the time frame covered by these bulletins.
2021 Cadillac XT6 · Electrical System · filed with NHTSA Oct 11, 2026 · ODI 11770401
Driving my vehicle with no warnings, messages, or symptoms on adaptive cruise control Sunday on in Michigan. I changed lanes into the right lane when the vehicle abruptly, without notification, and with force, caused braking that unexpectedly and dangerously slowed the vehicle then released braking before doing the same a moment later.
2021 GMC Terrain · Electrical System · filed with NHTSA Jul 1, 2025 · ODI 11670483
In depth: 2022 Chevrolet Silverado electrical problems → · 2021 Chevrolet Silverado electrical problems → · 2021 Chevrolet Tahoe electrical problems → · 2022 GMC Sierra electrical problems →
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 group493 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 |
|---|---|---|---|
| N262565450 | Service campaign | Oct 26, 2026 | Customer Satisfaction Program. Certain vehicles listed above may have a condition in which remanufactured high voltage battery packs were b… |
| N242468490-02 | Service campaign | May 28, 2026 | Certain vehicles may have missing cavity plugs from the rear chassis harness electrical connector. Dealers are to inspect the rear chassis h… |
| 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… |
| 24-NA-166 | Service bulletin | Nov 7, 2025 | This technical bulletin provides repair information to correct a customer concern of DTC C1171 C1172 C1173 C1174 Tire Pressure Monitor Senso… |
| 24-NA-227 | Service bulletin | Nov 4, 2025 | This technical bulletin provides repair information to correct a customer concern of Vibration Rattle or Boom at 1800 to 2000 RPM. |
| 25-NA-061 | Service bulletin | Oct 3, 2025 | This technical bulletin provides a procedure to correct the condition of Driver or Passenger Rear Door Handle Will Not Fold In. |
| 25-NA-074 | Service bulletin | Sep 4, 2025 | Some customers may comment on rear body structure stop lamp or rear closure signal lamp may be totally inoperative or staying illuminated. |
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.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM PIC6551 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 PIC6551 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 PIC6551 cover?
The manufacturer filed it against 54 model years across 4 brands (Chevrolet, GMC, Buick and Cadillac): 2022 Buick Enclave, 2021 Buick Enclave, 2022 Buick Encore, 2021 Buick Encore, 2022 Buick Envision, 2021 Buick Envision and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.