Ford bulletin 21B09 S2
What it saysCertain 2014-2020 Model Year Multiple Vehicle Lines 3G Telematics Control Unit to 4G Upgrade Kit REASON FOR THIS SUPPLEMENT Program Terms & Urgency / Expiration Date: Program extension until July 31, 2023. NHTSA’s full summary ↓
Ford filed this with NHTSA as a service bulletin dated Apr 12, 2023, received May 2, 2023, about the electrical system. It names 17 model years across Ford and Lincoln (2016–2020). 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: Ford · Lincoln.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationCertain 2014-2020 Model Year Multiple Vehicle Lines 3G Telematics Control Unit to 4G Upgrade Kit REASON FOR THIS SUPPLEMENT Program Terms & Urgency / Expiration Date: Program extension until July 31, 2023. Service Action: o IDS level 128 or higher is now required to address various programming issues encountered. o C-MAX Energi vehicles are now serviceable with new software and hardware. Labor Allowances: C-MAX labor has been updated. Parts Requirements / Ordering Information: o The C-MAX 4G Upgrade Kit is now orderable at this time with a new part number. o MKX Rear seat backrest nut claim quantity updated. Technical Information updates: o Ensure IDS level 128 or higher is used. o Toggling Valet Mode is no longer required. o C-MAX Energi instructions are now available. Owner Notification: Non-repaired vehicle owners will be mailed the week of April 17, 2023. Pickup and Delivery: Added Customer Acknowledgement Form - Review form contents with customer prior to kit ordering and obtain customer signature prior to installation for Focus BEV, C-MAX, and Fusion Energi vehicles.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 21B09 S2 | Service bulletin | Apr 12, 2023 | 10235323 | PDF, 23,556 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 themFord 10 model years
Lincoln 7 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 17 model years this bulletin names have filed 7,966 complaints with NHTSA since 2015. 881 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 2017 Ford Fusion, the 92 owners who gave an odometer reading for Electrical System reported it at a median of 29,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
When on freeway car suddenly displays an alert saying Stop safely now And will shut off , while driving makes it impossible to properly control the car . It has done this on multiple occasions, On the freeway , on residential streets and also when starting from park and proceeding to drive car has suddenly stopped and unable to restart…
2016 Ford Focus · Electrical System · filed with NHTSA Jul 7, 2024 · ODI 11599912
Now on my 3rd Battery in 3 months. A section in front of the battery gets very hot. It's a section with a lot of thick wires coming together. Most of the time my car will not start, I just have to keep moving wires until I get a connected for the car to start. I expecting the car to start a fire or a battery explosion pretty soon.
2017 Lincoln MKC · Electrical System · filed with NHTSA Jun 20, 2021 · ODI 11421544
The contact owns a 2017 Lincoln Mkx. The contact received NHTSA campaign number: 17v226000 (electrical system). The contact stated the manufacturer exceeded a reasonable amount of time for the recall repair. The vehicle was not diagnosed or repaired. The contact did not experience a failure. The manufacturer was not contacted.
2017 Lincoln MKX · Electrical System · filed with NHTSA Aug 11, 2020 · ODI 11348542
In depth: 2016 Ford Focus electrical problems → · 2020 Ford Fusion electrical problems → · 2019 Ford Fusion electrical problems → · 2017 Ford Fusion 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 group15 other manufacturer communications filed against these Ford models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Ford list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 25H05 S1 | Other | Apr 29, 2026 | Harvest Program 25H05 – Supplement #1 Certain 2011-2021 Model Year Vehicles Software Verification Harvest Program |
| 25N15 S1 | Other | Apr 20, 2026 | Customer Satisfaction Program 25N15 - Supplement #1 Certain 2015-2019 Model Year Multiple Vehicle Lines Rear View Camera Inspection For One… |
| SSM 54601 | Service bulletin | Feb 24, 2026 | Ford and Lincoln vehicles equipped with wired keyless entry keypad systems and accessory wireless keyless entry keypad systems may or may no… |
| SSM 54589 | Other | Feb 17, 2026 | Some 2019-2024 Ford and Lincoln vehicles equipped with SYNC3 may experience various connectivity concerns with The Ford App Lincoln App incl… |
| TSB 25-2570 | Service bulletin | Nov 26, 2025 | This article supersedes TSB 24-2165 to update the TSB Service Procedure. Some vehicles listed in the Model statement above may exhibit vario… |
| 25H05 | Other | Nov 19, 2025 | This is a proactive investigation program by Ford Motor Company to inspect a limited number of affected vehicles that are customer-owned. F… |
| SSM 54366 | Service bulletin | Nov 12, 2025 | Some 2015-2021 Ford and Lincoln vehicles may exhibit an illuminated MIL with diagnostic trouble codes (DTCs) P0011, P0012, P0014, P0015, P00… |
| SSM 54116 | Service bulletin | Aug 7, 2025 | Various 2019-2024 Ford and Lincoln vehicles equipped with SYNC 3 may experience a partially or fully black center display screen at start-up… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Ford and Lincoln, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Ford 21B09 S2 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 21B09 S2 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 21B09 S2 cover?
The manufacturer filed it against 17 model years across 2 brands (Ford and Lincoln): 2017 Ford C-MAX, 2016 Ford C-MAX, 2018 Ford Focus, 2017 Ford Focus, 2016 Ford Focus, 2020 Ford Fusion and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.