Ford Motor Company has announced a safety campaign addressing a software glitch in replacement Battery Energy Control Modules (BECMs) used in Mustang Mach-E vehicles with Lithium Iron Phosphate (LFP) batteries. The fix applies to both individual service components (NHTSA Equipment ID: 26E-063) and affected vehicles in the field (NHTSA Vehicle ID: 26V-582 / Ford Reference: 26S70).
The issue stems from replacement BECMs running uncalibrated software, which miscalculates long-term battery health and can result in sudden power loss or cell degradation. Here is a breakdown of what went wrong and the associated risks.
Understanding the Glitch
When a Mustang Mach-E receives a new BECM during service, the replacement module is designed to inherit the battery’s true historical State of Health (SOH). Instead, a software defect caused newly installed service parts (numbers PZ98-10B687-K* and PZ98-14C197-K*) to default to a 100% SOH reading.
This automatic reset creates a blind spot where onboard systems assume the battery is factory-fresh regardless of its actual age or condition.
The Safety Risks
An artificially inflated health metric introduces two primary hazards:
- Unexpected Loss of Drive Power: Because onboard systems overestimate true energy reserves, the instrument cluster displays more remaining range than the battery possesses. Drivers face sudden power caps or complete stalls while driving, elevating collision risks.
- Elevated Fire Risk: Incorrect health data throws off high-voltage charging limits. Over repeated DC Fast Charging (DCFC) sessions, this improper regulation promotes lithium plating inside the battery cells. Advanced lithium plating risks thermal venting, which can trigger a high-voltage battery fire.
Dashboard Warning Indicators
If the onboard computer detects severe power limits related to this mismatch, drivers will see specific dashboard alerts:
- Wrench Icon (Service Vehicle Soon)
- Turtle Icon (Reduced Power Mode)
Scope & Investigation Details
Ford’s Critical Concern Review Group launched a formal probe on July 7, 2026, after internal engineers flagged the default initialization flaw. Investigation teams confirmed the vulnerability spans spare BECM inventory used for warranty swaps and over-the-counter parts sales.
- Impacted Units: A highly targeted group of approximately 83 vehicles.
- Real-World Impact: Ford has recorded zero accidents, injuries, or fires associated with the flaw, along with zero field reports directly reporting SOH miscalculations.
- Action Approved: Ford’s Field Review Committee authorized formal service actions on September 1, 2026.
The Service Fix
Technicians at Ford dealerships will reflash the BECM software to restore accurate SOH tracking and inheritance. Official owner notification letters go out beginning November 8, 2026.
