Software Glitch Transforms Some Mustang Mach-Es Into "Electric Bricks" 

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by Tyler Durden
Saturday, Apr 17, 2021 - 03:30 PM

Just as Morgan Stanely released a new Autos & Shared Mobility research report a couple of months ago explaining how Tesla is losing market share to the Ford Mustang Mach-E. It appears Ford has run into a significant software hiccup for some of its Mach-Es, transforming them into "electric bricks." 

Some Mach-E owners reported the 12-volt battery inside their vehicle has discharged after charging the main battery pack, preventing the car from turning on, essentially transforming it into an electric brick.  

According to a new service bulletin posted by the Michigan automaker on the National Highway Traffic Safety Administration (NHTSA) website, Ford has addressed the problem.

"Some 2021 Mustang Mach-E vehicles built on or before 3-Feb-2021 may exhibit the 12-volt battery becoming discharged while the vehicle is plugged in during the high voltage charging process. This may be due to the parameters in the powertrain control module (PCM). To correct the condition, follow the Service Procedure to reprogram various modules starting with the PCM," the bulletin read. 

Here is the complete technical service bulletin:

The dying 12-volt batteries were first reported by The Verge, as furious Ford owners recently began populating on online forums about the issue. Some readers must be asking: Why do electric cars have separate 12-volt batteries from the main battery pack? 

The answer is simple: 

The battery that supplies power to the electric motors is extremely high voltage, and the 12-volt battery powers the vehicle's low-voltage parts. When the 12-volt battery discharges, the car can't be started.

In a statement provided to The Verge, Ford said owners must bring their Mach-Es to a dealer for the fix. So there are no over-the-air updates like a Tesla. 

"We are aware that a small number of Mustang Mach-E owners have had their 12V battery reach a low voltage condition. We proactively worked with early owners experiencing this issue to identify the root cause and a fix. In the rare instances where this still occurs, customers can now contact their local EV-certified Ford dealer to have the matter resolved."

Ford revealed to The Verge the problem would be fixable via wireless update "later this year." The automaker also said Mach-Es after Feb. 3 do not exhibit this problem. 

Ford wouldn't specify how many of its Mach-Es are affected by the software glitch, but nearly 7,000 have been delivered in the first three months of the year. 

With Ford quickly selling Mach-E's, the software glitch comes at an inopportune time as it battles Tesla for EV US market share.