TSB SSM-54991 — Ford Service bulletin
SSM-54991 is a service bulletin on file with NHTSA for the Ford Mustang Mach-E, 2023–2026 model years. A TSB is factory repair guidance, not a recall — the repair is not automatically free.
What the bulletin says. Some 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…
NHTSA's own summary of the document, quoted from the public manufacturer-communications file.
Vehicles and model years SSM-54991 names
| Vehicle | Model years |
|---|---|
| Ford Mustang Mach-E | 2023, 2024, 2025, 2026 |
Every document filed under SSM-54991
| Document ID | Filed | Type |
|---|---|---|
| SSM 54991 | July 8, 2026 | Service bulletin |
What SSM-54991 covers
Fuel system — the component vocabulary NHTSA files this communication under.
Questions buyers ask
What is TSB SSM-54991?
SSM-54991 is a service bulletin filed with NHTSA by Ford, covering the Ford Mustang Mach-E across the 2023–2026 model years. NHTSA's summary reads: Some 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…
Which vehicles does SSM-54991 cover?
NHTSA's file names Ford Mustang Mach-E (2023–2026). A bulletin number can be re-issued against more vehicles later, so check the model-year list on this page against your own.
Is TSB SSM-54991 a recall, and is the repair free?
No. SSM-54991 is repair guidance the manufacturer sent its dealers, not a safety defect finding. You pay for the work unless the vehicle is still under warranty. Recall repairs, by contrast, are always free.
How do I get the full text of SSM-54991?
Take the document ID to a dealer's service desk, or search NHTSA's manufacturer-communications records. This page carries every document ID filed under SSM-54991, its date, and NHTSA's own summary from the public file.
Every number on this page is a count of records in the federal complaint, recall, and investigation files published by NHTSA's Office of Defects Investigation. This page lists only what NHTSA's manufacturer-communications file records under SSM-54991. Check any specific vehicle's open recalls by VIN at nhtsa.gov/recalls.