Early models of the all-electric 2021 Mustang Mach-E have a battery issue that may leave owners struggling to start their vehicles despite its being fully charged, according to a technical service bulletin that Ford sent to federal regulators.
"Bad software is turning some Mustang Mach-Es into 'electric bricks,' " said a headline in TheVerge.com, a tech website that first reported news of the Mach-E battery problem Thursday. The brick term has been coined by Mach-E forum members seeking advice from one another online.
The March 25 technical service bulletin filed with the National Highway Traffic Safety Administration describes the situation in more technical terms: "12-Volt Battery Becomes Discharged While The Vehicle Is Plugged In During The High Voltage Charging Process."
Discharging, or draining, describes the process of a battery losing energy.
When this happens, Mach-E customers get notified by their FordPass app that the Mach-E is in "deep sleep" mode, TheVerge noted.
The issue affects vehicles built on or before Feb. 3, Ford said. While the company has touted the potential for over-the-air updates, this fix requires a dealer visit.
The Ford bulletin said the problem may be related to the powertrain control module. The company told Reuters the situation is a "software glitch, which results in the small battery discharging while a larger high-voltage battery pack is charging."
The Dearborn automaker declined to say how many Mach-E owners are affected. The company reported selling three vehicles in December, 238 in January and 3,739 in February.
"We are aware that a small number of Mustang Mach-E owners have had their 12-volt battery reach a low-voltage condition. We proactively worked with early owners experiencing this issue to identify the root cause and a fix," said Ford spokeswoman Emma Bergg. "In the rare instances where this still occurs, customers can now contact their local EV-certified Ford dealer to have the matter resolved."
On Jan. 17, the Free Press reported that Ford was holding the Mach-E for additional quality review. Bergg estimated the hold would last up to eight weeks for "several hundred" vehicles after being built at the factory in Cuautitlan, Izcalli, Mexico.