Back in late August, the National Highway Traffic Safety Administration (NHTSA) opened an investigation into select 2021-2022 Ford Mustang Mach-E models after a recall and stop-sale was issued following the discovery of a problem with the crossover’s high voltage battery main contactors. Several owners weren’t satisfied with Ford’s proposed fix for this problem, however, which could cause a total loss of power when the high voltage battery main contactors overheat from DC fast-charging and repeated wide-open throttle events, and a handful of lawsuits were filed as a result. Regardless, the NHTSA has now officially closed its investigation into this matter.
The NHTSA originally opened its investigation after 12 Ford Mustang Mach-E owners filed complaints claiming that their vehicles still had problems with overheating high voltage battery contactors after they received the original Ford fix, which involved installing a software update to monitor contactor temperature and reduce battery power to prevent damage, along with a Battery Energy Control Module (BECM) software update to monitor contactor resistance, identify overheating issues, and then reduce vehicle power to prevent further damage.
However, in October, Ford issued another recall acknowledging that these updates weren’t entirely effective, and instead, instructed dealers to replace the Bussed Electrical Center, or High Voltage Battery Junction Box. The NHTSA ultimately determined that this action was sufficient in rectifying the high-voltage contractor overheating issue, and as such, decided to close its investigation as a result.
“In view of the recall action taken by Ford, ODI (Office of Defects Investigations) is closing this investigation,” the agency wrote of its decision. “ODI will continue to monitor reports of this failure in both extended range and standard range models. The Agency reserves the right to take additional action if warranted by future circumstances. To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.”