Ford bulletin SSM 54991
What it saysSome 2023-2026 Mustang Mach-E vehicles equipped with a lithium iron/ion phosphate (LFP) standard range battery (minor feature code HTHAH) may exhibit a battery energy control module (BECM) state of health reading… NHTSA’s full summary ↓
Ford filed this with NHTSA as a service bulletin dated Jul 8, 2026, received Jul 13, 2026, about the fuel/propulsion system. It names 4 model years (2023–2026). 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 communicationSome 2023-2026 Mustang Mach-E vehicles equipped with a lithium iron/ion phosphate (LFP) standard range battery (minor feature code HTHAH) may exhibit a battery energy control module (BECM) state of health reading that over-estimates the actual high voltage battery state of health after a BECM replacement directed by the Workshop Manual (WSM). This may be due to the software in the BECM. To correct this condition, download and run the "BECM-High Voltage Battery Capacity Relearn" application using the Ford Diagnosis and Repair System (FDRS) scan tool. For claiming, use causal part 10B687 and labor operations 12651D and 12651D4. The engineering team is currently working on a permanent software solution which is expected to be available in Q4 of 2026.<br /><br /> If a vehicle exhibits this concern, submit a Global Concern Report (GCR). To submit a report, click on the "Submit Global Concern Report (GCR)" link at the upper right of the Professional Technician System (PTS) Vehicle ID screen (vehicle identification number ÝVIN¨ required) and fill out the form. Do not use the "Report A Problem" link to submit
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| SSM 54991 | Service bulletin | Jul 8, 2026 | 11034969 | 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 themA 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 4 model years this bulletin names have filed 192 complaints with NHTSA since 2015. 8 of them name Fuel/Propulsion 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.
Driving approaching a corner and suddenly the vehicle showed on screen "Stop Safely Now" coasting to a stop. Only 180 miles on car. 78 percent charge. 230 miles to empty. Once in Park couldn't move out of park. Ford towing service indicated 3 hours out. Stuck on corner in traffic at intersection in my mind a dangerous situation
2023 Ford Mustang Mach-E · Fuel/Propulsion System · filed with NHTSA Oct 5, 2023 · ODI 11548356
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 fuel/propulsion system
Source: same model, same component group5 other manufacturer communications filed against the Ford Mustang Mach-E under the same component group (fuel/propulsion system), newest first.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| SSM 54803 | Service bulletin | May 5, 2026 | Some 2025 Mustang Mach-E vehicles built on or before 30-Jun-2025 and 2024 F-150 Lightning vehicles may exhibit a flashing light on the air c… |
| TSB 26-2005 | Service bulletin | Jan 19, 2026 | This article supersedes TSB 25-2058 to update: service procedure enhancements, and increase labor operation allowances. Some of the vehicles… |
| TSB 25-2622 | Service bulletin | Jan 17, 2026 | Some of the vehicles listed in the Model statement above may exhibit at least one of the following conditions: * Stuck in park * "Service Ve… |
| SSM 54388 | Service bulletin | Nov 18, 2025 | Some 2021-2023 Mustang Mach-E vehicles equipped with nickel, cobalt and manganese (NCM) standard/extended range battery with minor feature c… |
| SSM 54334 | Service bulletin | Oct 28, 2025 | Some 2023-2025 Mustang Mach-E vehicles equipped with a lithium iron phosphate (LFP) standard range battery (minor feature code HTHAH) built… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Ford, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Ford SSM 54991 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 SSM 54991 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 SSM 54991 cover?
The manufacturer filed it against 4 model years: 2026 Ford Mustang Mach-E, 2025 Ford Mustang Mach-E, 2024 Ford Mustang Mach-E, 2023 Ford Mustang Mach-E. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.