GM bulletin PIP5621D
What it saysThis Preliminary information communicates to the dealer technician that TAC recommends the utilization of the GDS2 software to aid in diagnosing automatic transmission concerns. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Aug 24, 2023, received Sep 18, 2023, about the power train. It names 239 model years across Chevrolet, GMC, Buick and Cadillac (2016–2022). 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 the dealer technician that TAC recommends the utilization of the GDS2 software to aid in diagnosing automatic transmission concerns. TAC is requesting the GDS2 session logs be sent in before the dealer contacts TAC.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| PIP5621D | Service bulletin | Aug 24, 2023 | 10242309 | not found |
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 116 model years
and 75 more on this site: 2021 Chevrolet Express, 2020 Chevrolet Express, 2019 Chevrolet Express, 2018 Chevrolet Express, 2017 Chevrolet Express, 2016 Chevrolet Express, 2020 Chevrolet Impala, 2019 Chevrolet Impala, 2018 Chevrolet Impala, 2017 Chevrolet Impala, 2016 Chevrolet Impala, 2022 Chevrolet Malibu, 2021 Chevrolet Malibu, 2020 Chevrolet Malibu, 2019 Chevrolet Malibu, 2018 Chevrolet Malibu, 2017 Chevrolet Malibu, 2016 Chevrolet Malibu, 2017 Chevrolet SS, 2016 Chevrolet SS, 2021 Chevrolet Silverado, 2019 Chevrolet Silverado, 2018 Chevrolet Silverado, 2017 Chevrolet Silverado, 2022 Chevrolet Silverado 2500HD, 2020 Chevrolet Silverado 2500HD, 2019 Chevrolet Silverado 2500HD, 2018 Chevrolet Silverado 2500HD, 2017 Chevrolet Silverado 2500HD, 2016 Chevrolet Silverado 2500HD, 2020 Chevrolet Sonic, 2019 Chevrolet Sonic, 2018 Chevrolet Sonic, 2017 Chevrolet Sonic, 2016 Chevrolet Sonic, 2021 Chevrolet Spark, 2020 Chevrolet Spark, 2019 Chevrolet Spark, 2018 Chevrolet Spark, 2017 Chevrolet Spark, 2016 Chevrolet Spark, 2022 Chevrolet Suburban, 2021 Chevrolet Suburban, 2020 Chevrolet Suburban, 2019 Chevrolet Suburban, 2018 Chevrolet Suburban, 2017 Chevrolet Suburban, 2016 Chevrolet Suburban, 2022 Chevrolet Tahoe, 2021 Chevrolet Tahoe, 2020 Chevrolet Tahoe, 2019 Chevrolet Tahoe, 2018 Chevrolet Tahoe, 2017 Chevrolet Tahoe, 2016 Chevrolet Tahoe, 2022 Chevrolet Trailblazer, 2021 Chevrolet Trailblazer, 2022 Chevrolet Traverse, 2021 Chevrolet Traverse, 2020 Chevrolet Traverse, 2019 Chevrolet Traverse, 2018 Chevrolet Traverse, 2017 Chevrolet Traverse, 2016 Chevrolet Traverse, 2022 Chevrolet Trax, 2021 Chevrolet Trax, 2020 Chevrolet Trax, 2019 Chevrolet Trax, 2018 Chevrolet Trax, 2017 Chevrolet Trax, 2016 Chevrolet Trax, 2019 Chevrolet Volt, 2018 Chevrolet Volt, 2017 Chevrolet Volt, 2016 Chevrolet Volt.
Also filed against model years this site has no page for: 2019 Chevrolet Trailblazer.
GMC 42 model years
and 34 more on this site: 2021 GMC Canyon, 2020 GMC Canyon, 2019 GMC Canyon, 2018 GMC Canyon, 2017 GMC Canyon, 2016 GMC Canyon, 2022 GMC Savana, 2021 GMC Savana, 2020 GMC Savana, 2019 GMC Savana, 2018 GMC Savana, 2017 GMC Savana, 2016 GMC Savana, 2022 GMC Sierra, 2021 GMC Sierra, 2019 GMC Sierra, 2018 GMC Sierra, 2017 GMC Sierra, 2020 GMC Sierra 2500HD, 2016 GMC Sierra 2500HD, 2022 GMC Terrain, 2021 GMC Terrain, 2020 GMC Terrain, 2019 GMC Terrain, 2018 GMC Terrain, 2017 GMC Terrain, 2016 GMC Terrain, 2022 GMC Yukon, 2021 GMC Yukon, 2020 GMC Yukon, 2019 GMC Yukon, 2018 GMC Yukon, 2017 GMC Yukon, 2016 GMC Yukon.
Buick 36 model years
and 28 more on this site: 2018 Buick Enclave, 2017 Buick Enclave, 2016 Buick Enclave, 2022 Buick Encore, 2021 Buick Encore, 2020 Buick Encore, 2019 Buick Encore, 2018 Buick Encore, 2017 Buick Encore, 2016 Buick Encore, 2022 Buick Envision, 2021 Buick Envision, 2020 Buick Envision, 2019 Buick Envision, 2018 Buick Envision, 2017 Buick Envision, 2016 Buick Envision, 2019 Buick LaCrosse, 2018 Buick LaCrosse, 2017 Buick LaCrosse, 2016 Buick LaCrosse, 2020 Buick Regal, 2019 Buick Regal, 2018 Buick Regal, 2017 Buick Regal, 2016 Buick Regal, 2017 Buick Verano, 2016 Buick Verano.
Cadillac 45 model years
and 37 more on this site: 2021 Cadillac CT5, 2020 Cadillac CT5, 2020 Cadillac CT6, 2019 Cadillac CT6, 2018 Cadillac CT6, 2017 Cadillac CT6, 2016 Cadillac CT6, 2019 Cadillac CTS, 2018 Cadillac CTS, 2017 Cadillac CTS, 2016 Cadillac CTS, 2016 Cadillac ELR, 2022 Cadillac Escalade, 2021 Cadillac Escalade, 2020 Cadillac Escalade, 2019 Cadillac Escalade, 2018 Cadillac Escalade, 2017 Cadillac Escalade, 2016 Cadillac Escalade, 2016 Cadillac SRX, 2022 Cadillac XT4, 2021 Cadillac XT4, 2020 Cadillac XT4, 2019 Cadillac XT4, 2022 Cadillac XT5, 2021 Cadillac XT5, 2020 Cadillac XT5, 2019 Cadillac XT5, 2018 Cadillac XT5, 2017 Cadillac XT5, 2022 Cadillac XT6, 2021 Cadillac XT6, 2020 Cadillac XT6, 2019 Cadillac XTS, 2018 Cadillac XTS, 2017 Cadillac XTS, 2016 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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What owners reported
Source: NHTSA complaint databaseOwners of the 238 model years this bulletin names have filed 31,704 complaints with NHTSA since 2015. 6,976 of them name Power Train — 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 2017 GMC Acadia, the 156 owners who gave an odometer reading for Power Train reported it at a median of 36,128 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
I Took My Car To Castle Villa Park On July 8 2025 And Explained To Tony That Check My Car In That It Sound As If It Was A Hub Bearing My Car Was Dropped Off At 7:00 AM Until Around 1:00PM I Was Told I Need A Tire To See If It Was My Hub Bearing Which Didn’t Make Sense To Me So I Ask For A Supervisor I Was Then Inform That They Could Tell…
2020 Chevrolet Impala · Power Train · filed with NHTSA Jul 20, 2025
The contact owns a 2020 Cadillac CT6. The contact stated while driving 65 MPH, the transmission seized, and the vehicle was coasted over to the right side of the roadway while waiting for tow service. A dealer as contacted. The vehicle was towed to the dealer where it was diagnosed with transmission failure. The vehicle was not repaired.
2020 Cadillac CT6 · Power Train · filed with NHTSA Jul 15, 2025
The contact owns a 2020 Cadillac CT6. The contact received notification of NHTSA Campaign Number: 25V148000 (Power Train); however, the part to do the recall repair was unavailable. The contact stated that while his wife was driving at an undisclosed speed, the vehicle jerked before slamming into gear. No warning lights were illuminated.
2020 Cadillac CT6 · Power Train · filed with NHTSA Jun 17, 2025
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 power train
Source: same model, same component group233 other manufacturer communications filed against these GM models under the same component group (power train), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N262567720 | Service campaign | Sep 17, 2026 | Certain vehicles may have received transmission mounting bolts that do not meet expected hardness specifications. Loose or failed bolts may… |
| N252502891-01 | Service campaign | Aug 20, 2026 | Certain vehicles may have a condition in which the internal differential nut was cross threaded or missing during assembly. Dealers will rev… |
| N252502890-01 | Service campaign | Aug 20, 2026 | Certain vehicles may have a condition in which the internal differential nut was cross threaded or missing during assembly. Dealers will rev… |
| N242471460-01 | Service campaign | Aug 20, 2026 | Certain vehicles may have been built with an Electric Drive Unit mounting bolt that is too long, causing damage to the Drive Unit case. Deal… |
| N262556930-01 | Service campaign | Jun 17, 2026 | Certain vehicles may have a condition in which the transfer case drive chain sprocket is cracked. Dealers are to replace the transfer case. |
| N262560680 | Service campaign | Jun 10, 2026 | Certain vehicles may have a condition in which the bolts for the transmission control valve body may be loose or missing. Dealers will retor… |
| N262556930 | Service campaign | Jun 2, 2026 | Certain vehicles may have a condition in which the transfer case drive chain sprocket is cracked. Dealers are to replace the transfer case. |
| N252517790 | Service campaign | Oct 14, 2025 | Certain vehicles, equipped with 8L80 or 8L90 Transmissions, may have a condition in which the reaction carrier cracks. Dealers are to replac… |
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 PIP5621D 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 PIP5621D 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 PIP5621D cover?
The manufacturer filed it against 239 model years across 4 brands (Chevrolet, GMC, Buick and Cadillac): 2019 Buick Cascada, 2018 Buick Cascada, 2017 Buick Cascada, 2016 Buick Cascada, 2022 Buick Enclave, 2021 Buick Enclave and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.