Recall affects just 86 Mustang Mach-Es. Replacement controllers can falsely report battery health. Ford warns of power loss and potential fire risk. There are few things an EV driver needs to trust more than the little number telling them how much battery is left. Unfortunately, 86 Ford Mustang Mach-E owners may have discovered an unusually creative way for that number to lie. Ironically, the problem only exists because their cars were previously repaired. Ford is recalling certain 2023-2025 Mustang Mach-Es equipped with lithium iron phosphate (LFP) batteries after discovering an issue involving replacement Battery Energy Control Modules, or BECMs. According to the automaker, every one of the 86 vehicles included in the recall is estimated to have the defect. Read: Ford Recalls 288,000 Explorers Because The Roof Trim Keeps Flying Off The problem is almost comically simple. When a replacement BECM was installed, it initialized the battery’s State of Health at a fresh-from-the-factory 100 percent instead of inheriting the actual State of Health from the battery already in the vehicle. That’s considerably more consequential than simply being off by a percentage or two. Since the car believes its battery is healthier than it really is, Ford says it can also display an artificially high State of Charge on the instrument cluster. In other words, the Mach-E can tell its driver that there’s more juice in the tank than there actually is. That discrepancy can eventually cause unexpected power limitation and ultimately a complete loss of motive power. Drivers may see a wrench or turtle warning light as the vehicle begins limiting power. There is another, potentially more serious concern. Ford says the incorrect State of Health calculation may increase lithium plating within the battery cells as DC fast-charging cycles accumulate. Severe lithium plating can increase the risk of thermal venting and, potentially, a vehicle fire. Thankfully, there’s no indication that things have reached that point. As of its filing, Ford said it wasn’t aware of any crashes, injuries, or fires related to the issue. It also hadn’t identified any field reports specifically tied to the State of Health overestimation problem. The solution is a simple software update that will allow the BCEM to recognize and then use the actual state of health that the corresponding battery has. It’s an extremely small recall, but also a fascinating reminder of just how much modern EVs rely on software knowing exactly what’s happening inside the battery. Photos: Ford