Jaguar Land Rover has widened a recall over a failing DC-DC converter to 193,846 vehicles, after filing a new campaign covering 23,677 additional mild-hybrid SUVs on top of the 170,169 it recalled for the same part back in April 2026. The defect can knock out a vehicle’s 12-volt electrical system entirely, cutting drive power and exterior lighting at once rather than causing a gradual warning-light buildup. What makes the expansion notable is not just its size but its cause: the parts engineers blamed in April turned out not to be the real problem.
The original recall pinned the failure on “an internal fault in the boost-control microchip” inside an older generation of converter, according to the National Highway Traffic Safety Administration filing Jaguar Land Rover submitted that April, which put the affected population at 170,169 vehicles built between the 2019 and 2024 model years. Engineers assumed replacing or reflashing that hardware would close the case, and the automaker mailed interim warning letters on that basis within three months.
A hardware fix that missed the real cause
It did not. Investigators later found that the newer converters covered by this expansion were failing in a different way entirely, one that had nothing to do with the microchip flagged in the April filing. The follow-up recall filing attributes the failure instead to “an electrical overload that can occur during high power demand” combined with a software error that can prevent the converter from operating properly at startup. Jaguar Land Rover’s engineering team, as autoevolution reported, effectively started over: having ruled out the hardware, “the task force switched gears and went after the code.”
That pivot matters because it means the fix is different, too. Where the April campaign called for updating central software tied to the suspect chip, the September filing calls for a broader reflash meant to balance electrical loads and patch the startup sequence, plus a new limp-mode function meant to keep a failing vehicle drivable rather than dead at the roadside.
How one failed converter cascades through the electrics
A DC-DC converter’s job in a 48-volt mild-hybrid system is unglamorous but load-bearing: it bridges the higher-voltage hybrid battery to the vehicle’s ordinary 12-volt network, so that energy recovered under braking can also run the radio, the headlights and the power windows rather than sitting stranded in a separate system, as engineers who design these systems explain. When it fails, that bridge does not degrade slowly; it drops out.
Owners affected by the fault have reported the failure arriving as a cascading sequence rather than a single warning: dashboard messages, a disabled lane-keep-assist system, suspension and stability-control faults, and gearbox errors, ending in the loss of both drive power and exterior lighting at once. NHTSA’s own language for the consequence is blunter. “A loss of drive power increases the risk of a crash,” the agency’s recall filing states, the same sentence used for both the April and September campaigns because the end result, if not the cause, is identical.
Nine model lines carry the expanded recall, spanning Land Rover’s Range Rover, Range Rover Sport, Range Rover Velar, Discovery, Discovery Sport and Defender alongside Jaguar’s F-Pace and E-Pace, with model years running from 2019 through 2024 depending on the line.
The timeline for the newest 23,677 owners
Owners newly swept into the September expansion will wait longer than that first group did. Jaguar Land Rover’s filing sets their interim-letter mailing for November 13, 2026, nearly two months after regulators received the paperwork on September 17, roughly double the gap the automaker managed the first time around. In both cases the interim letter is only a warning, not a repair; the actual remedy is a free dealer software update, and Jaguar Land Rover has not yet said when that update will reach either group of owners, or whether the fix rolling out to the newly added 23,677 vehicles will also be pushed to the original 170,169 as a precaution. Anyone unsure whether their SUV falls into either population can run its VIN through NHTSA’s public recall lookup rather than wait for a letter to arrive.
Dealers, meanwhile, are working from two separate remedy instructions for what customers experience as the same failure. A service technician checking a Range Rover Sport in for the April campaign is following different software instructions than one working on a Defender caught by the September filing, even though both vehicles can fail in the same way at the roadside: no drive power, no exterior lights, and a 12-volt system with nowhere left to draw from.
Whether 193,846 is the final number remains an open question. The same investigative shift that expanded April’s 170,169 into September’s 23,677 additional vehicles was itself the product of engineers discovering a second failure mode after they thought the first one was fixed, and Jaguar Land Rover has not said whether every converter variant in the fleet has now been tested against both.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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