Toyota is recalling 8,521 battery-electric 2026 C-HR crossovers in the United States because a software programming error can overcharge the drive battery and shut down the electric drive system, causing a sudden loss of drive power. The company reported the problem to federal regulators on Sept. 2, 2026. Owner letters began going out in the weeks around Oct. 19.
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Toyota reported no field reports and no U.S. warranty claims tied to the condition as of Aug. 26, 2026, and the fix is a free software update that a dealer must perform.
A charging parameter that was wrong in the controller
The National Highway Traffic Safety Administration lists the action as campaign 26V570000, under the electrical system, propulsion heading, with 8,521 potentially affected vehicles and Toyota’s own recall number 26TA17. Its summary says the programming error can overcharge the electric drive system battery under certain driving conditions, shutting down the drive system and causing a loss of drive power, and its consequence line says an unexpected loss of drive power increases the risk of a crash.
Toyota’s defect report to the agency is more specific. A software parameter in the battery electric vehicle control unit, the part that governs battery charging, is incorrect, and two Denso control-unit part numbers, 89980-42G40 and 89980-42G50, carry it. The vehicles were built between Feb. 6 and July 10, 2026, and Toyota estimated that all of them have the defect, though not all units in the production range were sold in the United States.
The conditions that trigger an overcharge
The report names three conditions that must coincide: the battery is already highly charged, the temperature is low, and the vehicle stays in regenerative braking for a long stretch, such as a long downhill coast. Under those conditions the battery can be pushed past its limit and the drive system shuts down, which the report says would cause a loss of power at higher speeds. Warning lights and a buzzer signal the shutdown.
Carscoops’ Michael Gauthier, in a Sept. 11 article, illustrated the scenario with a fully charged C-HR driven down from mountains into a city while leaning heavily on regenerative braking. He also reported that Toyota had found the issue in April 2026 while testing a future battery-electric model, which led engineers to check the control units in other electric vehicles and identified the C-HR.
From April test finding to October letters
Toyota’s chronology in the report is orderly. The incorrect parameter turned up in late April during development testing of a future model. Bench and simulation testing in July confirmed that overcharging could shut down the drive system. Toyota decided on Aug. 28 to conduct a voluntary recall, and the report was submitted on Sept. 2, three working days later and inside the five-working-day window set by 49 CFR 573.6.
Dates differ slightly between documents. The report planned phased owner notification from Oct. 18 to Nov. 1, 2026, while the federal campaign record states that letters were mailed on Oct. 19. Both place the first notices in the second half of October. The report also records an interim advisory telling owners not to drive the vehicle and to park it outside until the remedy is applied, although the agency’s summary flags for the campaign show park-it and park-outside as false, so owners should read their letter closely for the instruction that applies.
The remedy is a software update. Dealers will update the battery electric vehicle control unit software at no charge, and the report says the letters will go out within the New Vehicle Limited Warranty period, so the repair is covered under warranty. The federal record lists no over-the-air update, which means the update has to be done in person at a dealer. Toyota customer service is at 1-800-331-4331.
Owners who want to confirm a vehicle can use NHTSA’s recall lookup with the 17-character VIN. The recall covers the 2026 C-HR battery-electric model only, so it does not apply to other Toyota vehicles. Carscoops noted that Toyota announced a second, unrelated recall around the same time for 135 vehicles with incorrect load-capacity labels, a separate action with its own remedy.
The shape of the defect is worth noting for anyone who drives an electric vehicle in cold, hilly country. A battery that is full cannot take much regenerative energy, and the controller’s job is to manage that limit. In these C-HRs, the report says the charging parameter in the control unit is incorrect, so the protection that should keep the battery within limits does not act as intended, and a long descent in cold weather with a full pack is the case it describes. Toyota’s decision to recall before any customer report reached it, as the document’s no-claims statement indicates, means the repair arrives ahead of any recorded failure on the road.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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