Porsche bulletin No. 28-26
What it saysTechnical information on Transmission Warning Message “P Not Available”, Fault Memory Entries for Parking Lock Buttons in the Shift Console and Transmission Electronics (PDK) Control Units ( NHTSA’s full summary ↓
Porsche filed this with NHTSA as a service bulletin dated Sep 22, 2026, received May 6, 2026, about the power train — 3 documents under this number. It names 47 model years (2016–2026). 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.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationTechnical information on Transmission Warning Message “P Not Available”, Fault Memory Entries for Parking Lock Buttons in the Shift Console and Transmission Electronics (PDK) Control Units (
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| No. 28-26 | Service bulletin | Sep 22, 2026 | 11037816 | PDF, 58 KB |
| No. 28-26 | Service bulletin | May 5, 2026 | 11033369 | PDF, 89 KB |
| No. 28-26 | Service bulletin | Apr 8, 2026 | 11032272 | PDF, 95 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 themAlso filed against model years this site has no page for: 2017 Porsche 718; 2017 Porsche 718 Boxster S; 2018 Porsche 718 Boxster S; 2019 Porsche 718 Boxster S; 2017 Porsche 718 Cayman S; 2018 Porsche 718 Cayman S; 2019 Porsche 718 Cayman S; 2018 Porsche 718 Spyder; 2019 Porsche 718 Spyder; 2016 Porsche 918 Spyder.
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 37 model years this bulletin names have filed 418 complaints with NHTSA since 2015. 150 of them name Electrical System, Engine, 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.
The contact owns a 2018 Porsche 718 Cayman. The contact stated that while the spouse was driving the vehicle at 70 MPH, abnormal handling occurred, followed immediately by a loud knocking noise. The driver pulled the vehicle to the side of the road and discovered the rear left axle had fractured, detached, and was hanging on the ground.
2018 Porsche Cayman · Power Train · filed with NHTSA Oct 16, 2026 · ODI 11771621
The contact owns a 2018 Porsche Panamera. The contact received notification of the NHTSA Campaign Number: 23V033000 (Electrical System) however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair.
2018 Porsche Panamera · Electrical System · filed with NHTSA May 8, 2023 · ODI 11520904
While driving my 2019 Porsche Cayenne S on the freeway, the check-engine light came on, followed by a message on the dashboard that read “Engine Control fault – Driving permitted – Visit workshop.” Moments later, the vehicle suddenly lost power and decelerated from about ~75 mph to around 55 mph, even though my foot was still on the…
2019 Porsche Cayenne · Engine · filed with NHTSA Nov 9, 2025 · ODI 11698394
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 group57 other manufacturer communications filed against these Porsche models under the same component group (power train), newest first. The eight newest are listed; the rest are on the Porsche list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| No. 91-26 | Service bulletin | Sep 24, 2026 | Technical Information for Particles/Metal Chips/Residues in Engine Oil |
| No. 72-26 | Service bulletin | Sep 23, 2026 | Symptom-based workshop manual for High-Pitched “Whining” and Whistling Noises in Partial Load Operation from the Engine Area. Note that this… |
| No. 30-26 | Service bulletin | Sep 22, 2026 | Manufacturer's Certificate for Overview of Approved Porsche C20 Engine Oils |
| No. 27-26 | Service bulletin | Sep 22, 2026 | Manufacturer's Certificate for Overview of Approved Porsche C20 Engine Oils. Note that the bulletin covers all models back to model year 198… |
| No. 26-26 | Service bulletin | Sep 22, 2026 | Manufacturer's Certificate for Overview of Approved Porsche C30 Engine Oils. Note that the bulletin includes all models back to model year 1… |
| No. 62-26 | Service bulletin | Sep 1, 2026 | Technical Information for Coolant Warning Light Lights Up: Suspected Coolant Loss on the Coolant Pump |
| 51/26 | Service bulletin | Jul 30, 2026 | Shrill Humming/Clacking Noise from the Engine Compartment: Check Mounting/Fastening of the ATF Cooler and/or ATF Lines (SY 51/26) |
| 18/26 | Warranty extension | Jul 23, 2026 | Warranty Information: Warranty Extension for Transmission Electronics Control Unit (18/26) |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Porsche, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Porsche No. 28-26 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 No. 28-26 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 Porsche warranty extension on file lists the ones Porsche has filed.
Which vehicles does No. 28-26 cover?
The manufacturer filed it against 47 model years: 2020 Porsche 718, 2026 Porsche 911, 2025 Porsche 911, 2024 Porsche 911, 2023 Porsche 911, 2022 Porsche 911 and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.