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Toyota Motor Engineering & Manufacturing (NYSE: TM, 7203T) is recalling ~21,000 model-year 2026 Toyota BZ, Lexus RZ, and Subaru Solterra battery electric vehicles. The Denso-supplied electronic control unit (Battery ECU) that controls the high-voltage battery may experience a fault, resulting in a sudden loss of drive power.
“Toyota observed certain diagnostic data during development testing of a new Plug-in Hybrid Electric Vehicle (PHEV) model. After investigation, Toyota found that the memory in the battery ECU can fail an operation check because a part of the memory address location utilized by the battery control IC overlaps with a part utilized by the monitoring IC. The monitoring IC could repeatedly overwrite data at the same memory address used by the battery control IC when the memory operational check cycle matches the monitoring IC’s write operation cycle,” Toyota said in the mandatory safety defect recall filling made published by the National Highway Traffic Safety Administration (NHTSA) this morning.
“However, Toyota determined that, even though similar software is utilized for certain BEV models being introduced to the market, the same condition would not occur because of a difference in the cycling of the monitoring IC’s write operation,” Toyota said.
Dealers will update the battery ECU software, free of charge as required by U.S. safety legislation [49 CFR § 573 – AutoCrat.] Owner notification letters are not expected to be mailed until 3 August 2026. Owners may contact Toyota’s customer service at 1-800-331-4331. Toyota’s numbers for this recall are 26LA07 and 26TA11. Subaru’s number for this recall is WRG26.
Chronology as Filed
August 2025 – September 2025: Toyota observed certain diagnostic data during development testing of a new Plug-in Hybrid Electric Vehicle (PHEV) model. After investigation, Toyota found that the memory in the battery ECU can fail an operation check because a part of the memory address location utilized by the battery control IC overlaps with a part utilized by the monitoring IC. The monitoring IC could repeatedly overwrite data at the same memory address used by the battery control IC when the memory operational check cycle matches the monitoring IC’s write operation cycle. However, Toyota determined that, even though similar software is utilized for certain BEV models being introduced to the market, the same condition would not occur because of a difference in the cycling of the monitoring IC’s write operation.
April 2026 – June 2026: In April 2026: Toyota conducted a planned review of vehicle remote diagnostic data of the subject BEV models after the start of mass production to reconfirm its prior determination. In this review of these BEV models with a certain battery type, Toyota found the diagnostic data that is associated with the malfunction that Toyota previously investigated. After the review of the results of the remote diagnostic data in April, Toyota began bench testing and found that for a certain battery type of the BEV models, there is a possibility that the overwriting of the same memory address location by the two ICs could occur repeatedly when the cycle of the CPU’s memory operational check becomes longer, which could be caused by an increase in the CPU load (e.g., during low state of charge).
After the review of the results of the remote diagnostic data in April, Toyota began bench testing and found that for a certain battery type of the BEV models, there is a possibility that the overwriting of the same memory address location by the two ICs could occur repeatedly when the cycle of the CPU’s memory operational check becomes longer, which could be caused by an increase in the CPU load (e.g., during low state of charge).
Toyota conducted vehicle testing to evaluate vehicle behavior if this issue occurs. It was found that a warning message is displayed along with multiple illuminated warning indicators. However, the power steering and braking functions remain operational. The electric drive system was confirmed to be affected and will subsequently shut down, potentially resulting in a loss of motive power at any driving speed. In addition, an engineering analysis was conducted to see if other systems are affected by this issue and found that certain systems such as PCS and VSC could become inoperable.
June 12, 2026: Based on the results of the above investigation, Toyota decided to conduct a voluntary safety recall campaign. As of 11 June 2026, based on a diligent review of records, Toyota’s best engineering judgment is that there are no Toyota Field Technical Reports and 1 warranty claim that have been received from U.S. sources that relate or may relate to this condition.
*AutoInformed on
About Ken Zino
Ken Zino, editor and publisher of AutoInformed, is a versatile auto industry participant with global experience spanning decades in print and broadcast journalism, as well as social media. He has automobile testing, marketing, public relations and communications experience. He is past president of The International Motor Press Assn, the Detroit Press Club, founding member and first President of the Automotive Press Assn. He is a member of APA, IMPA and the Midwest Automotive Press Assn.
He also brings an historical perspective while citing their contemporary relevance of the work of legendary auto writers such as Ken Purdy, Jim Dunne or Jerry Flint, or writers such as Red Smith, Mark Twain, Thomas Jefferson – all to bring perspective to a chaotic automotive universe.
Above all, decades after he first drove a car, Zino still revels in the sound of the exhaust as the throttle is blipped during a downshift and the driver’s rush that occurs when the entry, apex and exit points of a turn are smoothly and swiftly crossed. It’s the beginning of a perfect lap.
AutoInformed has an editorial philosophy that loves transportation machines of all kinds while promoting critical thinking about the future use of cars and trucks.
Zino builds AutoInformed from his background in automotive journalism starting at Hearst Publishing in New York City on Motor and MotorTech Magazines and car testing where he reviewed hundreds of vehicles in his decade-long stint as the Detroit Bureau Chief of Road & Track magazine. Zino has also worked in Europe, and Asia – now the largest automotive market in the world with China at its center.
Sudden EV Power Loss – Toyota BZ, Lexus RZ, Subaru Solterra Recalled
Click for more.
Toyota Motor Engineering & Manufacturing (NYSE: TM, 7203T) is recalling ~21,000 model-year 2026 Toyota BZ, Lexus RZ, and Subaru Solterra battery electric vehicles. The Denso-supplied electronic control unit (Battery ECU) that controls the high-voltage battery may experience a fault, resulting in a sudden loss of drive power.
“Toyota observed certain diagnostic data during development testing of a new Plug-in Hybrid Electric Vehicle (PHEV) model. After investigation, Toyota found that the memory in the battery ECU can fail an operation check because a part of the memory address location utilized by the battery control IC overlaps with a part utilized by the monitoring IC. The monitoring IC could repeatedly overwrite data at the same memory address used by the battery control IC when the memory operational check cycle matches the monitoring IC’s write operation cycle,” Toyota said in the mandatory safety defect recall filling made published by the National Highway Traffic Safety Administration (NHTSA) this morning.
“However, Toyota determined that, even though similar software is utilized for certain BEV models being introduced to the market, the same condition would not occur because of a difference in the cycling of the monitoring IC’s write operation,” Toyota said.
Dealers will update the battery ECU software, free of charge as required by U.S. safety legislation [49 CFR § 573 – AutoCrat.] Owner notification letters are not expected to be mailed until 3 August 2026. Owners may contact Toyota’s customer service at 1-800-331-4331. Toyota’s numbers for this recall are 26LA07 and 26TA11. Subaru’s number for this recall is WRG26.
Chronology as Filed
August 2025 – September 2025: Toyota observed certain diagnostic data during development testing of a new Plug-in Hybrid Electric Vehicle (PHEV) model. After investigation, Toyota found that the memory in the battery ECU can fail an operation check because a part of the memory address location utilized by the battery control IC overlaps with a part utilized by the monitoring IC. The monitoring IC could repeatedly overwrite data at the same memory address used by the battery control IC when the memory operational check cycle matches the monitoring IC’s write operation cycle. However, Toyota determined that, even though similar software is utilized for certain BEV models being introduced to the market, the same condition would not occur because of a difference in the cycling of the monitoring IC’s write operation.
April 2026 – June 2026: In April 2026: Toyota conducted a planned review of vehicle remote diagnostic data of the subject BEV models after the start of mass production to reconfirm its prior determination. In this review of these BEV models with a certain battery type, Toyota found the diagnostic data that is associated with the malfunction that Toyota previously investigated. After the review of the results of the remote diagnostic data in April, Toyota began bench testing and found that for a certain battery type of the BEV models, there is a possibility that the overwriting of the same memory address location by the two ICs could occur repeatedly when the cycle of the CPU’s memory operational check becomes longer, which could be caused by an increase in the CPU load (e.g., during low state of charge).
After the review of the results of the remote diagnostic data in April, Toyota began bench testing and found that for a certain battery type of the BEV models, there is a possibility that the overwriting of the same memory address location by the two ICs could occur repeatedly when the cycle of the CPU’s memory operational check becomes longer, which could be caused by an increase in the CPU load (e.g., during low state of charge).
Toyota conducted vehicle testing to evaluate vehicle behavior if this issue occurs. It was found that a warning message is displayed along with multiple illuminated warning indicators. However, the power steering and braking functions remain operational. The electric drive system was confirmed to be affected and will subsequently shut down, potentially resulting in a loss of motive power at any driving speed. In addition, an engineering analysis was conducted to see if other systems are affected by this issue and found that certain systems such as PCS and VSC could become inoperable.
June 12, 2026: Based on the results of the above investigation, Toyota decided to conduct a voluntary safety recall campaign. As of 11 June 2026, based on a diligent review of records, Toyota’s best engineering judgment is that there are no Toyota Field Technical Reports and 1 warranty claim that have been received from U.S. sources that relate or may relate to this condition.
*AutoInformed on
About Ken Zino
Ken Zino, editor and publisher of AutoInformed, is a versatile auto industry participant with global experience spanning decades in print and broadcast journalism, as well as social media. He has automobile testing, marketing, public relations and communications experience. He is past president of The International Motor Press Assn, the Detroit Press Club, founding member and first President of the Automotive Press Assn. He is a member of APA, IMPA and the Midwest Automotive Press Assn. He also brings an historical perspective while citing their contemporary relevance of the work of legendary auto writers such as Ken Purdy, Jim Dunne or Jerry Flint, or writers such as Red Smith, Mark Twain, Thomas Jefferson – all to bring perspective to a chaotic automotive universe. Above all, decades after he first drove a car, Zino still revels in the sound of the exhaust as the throttle is blipped during a downshift and the driver’s rush that occurs when the entry, apex and exit points of a turn are smoothly and swiftly crossed. It’s the beginning of a perfect lap. AutoInformed has an editorial philosophy that loves transportation machines of all kinds while promoting critical thinking about the future use of cars and trucks. Zino builds AutoInformed from his background in automotive journalism starting at Hearst Publishing in New York City on Motor and MotorTech Magazines and car testing where he reviewed hundreds of vehicles in his decade-long stint as the Detroit Bureau Chief of Road & Track magazine. Zino has also worked in Europe, and Asia – now the largest automotive market in the world with China at its center.