12-Volt Batteries in Some 2021 Ford Mach-Es Are Failing

• Some Mach-E owners have reported the 12-volt batteries in their vehicles were dead after charging, preventing those cars from starting.

• Ford filed a service bulletin with NHTSA saying that a software glitch is responsible for the 12-volt battery dying.

• The affected Mach-Es were manufactured prior to February 3, and owners of the affected vehicles can have the issue resolved at a dealership.

Some owners of the electric 2021 Ford Mustang Mach-E have charged their vehicles only to realize their Mach-Es won’t start. As a result of a software glitch, the 12-volt batteries in some Mach-Es have died while the larger battery pack is charging, according to a service bulletin posted by Ford on the National Highway Traffic Safety Administration (NHTSA) website.

The dying batteries were first reported by The Verge, as owners had begun noting the problem on online forums. The reason an electric vehicle needs a 12-volt battery is because the battery which supplies power to the electric motors is high voltage, and the 12-volt battery powers many of the low-voltage parts of the car. When the 12-volt battery dies, the car can’t be started.

In a statement provided to Car and Driver, Ford wouldn’t specify how many of its Mach-Es are affected by the software glitch, but only those manufactured before February 3 have the glitch. Owners of the affected Mach-Es have to take their cars to a dealership in order to have the problem resolved; it won’t be until later this year that an over-the-air update could fix the problem.