2026 Lexus Rx

(1)The original 12-V battery was replaced by the dealership on XXX (after 5-week and 120-mile usage) with a new one, model: 00544-MFH50, S/N [XXX], 540CCA and 100 RC. (2)Upon double-checking with the 2026 Lexus Owner’s Manual for RX450H+, on Page 605, it clearly stated that when replacing the battery, its case size should be the same as the previous one (LN3) ……. with a performance rating of CCA of 603A or higher. (3)The dealership indicated the 00544-MFH50 was the right battery based on the VIN number per Lexus internal database. The database also showed another battery model: 28800-31572. (4)However, according to the battery information at [XXX], both 00544-MFH50 and 28800-31572 are listed as “Does not fit” the 2026 RX450H+ vehicle. (5)The other battery, model 00544-21171LXPR, is listed as the HV 12-V battery for the 2026 RX450H+ at [XXX]. (6)Also on the Lexus parts website, this 2026 RX450H+ VIN number is recognized as RX350h (Base Trim), a totally different vehicle. It may be possible that the Lexus 2026 RX450H+ Owner’s Manual (published in [XXX], 2026, for the North American market) and [XXX] have been updated with the correct 12-V battery information, while the internal Lexus database was not. It was not clear whether factories in [XXX] or elsewhere, and [XXX] dealerships, still use the possibly outdated and conflicting information for initial battery installation and replacement when needed. The discrepancies between Lexus internal information (manufacturing and dealership) and publicly available information from the owner’s manual and official Lexus website caused significant confusion about which battery is the right one designed for this vehicle in 2026. Details please see attachment. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The 12-V battery of a brand-new Lexus RX450h+ died suddenly without any warning, only about 5 weeks into regular driving, with ~120 miles on the odometer. Lexus Roadside Assistance was called in to jump-start the battery, and the vehicle was driven directly to the dealership (about 5 miles away) for service. The dealership service checked the battery and indicated it “passed” all tests and is in "good" condition. However, the service technicians could not identify or suggest any reason for such a sudden death of virtually a brand-new battery (5-week new, 120-mile usage). The dealership indicated that there is nothing they can do for the battery because Lexus warranty protocol would not allow them to replace it. The Lexus Engagement Center was also contacted, and they indicated that, per Lexus protocols, they could not do anything about it, except documentation on the battery failure and file it for future reference. The customer considered this suddenly “failed” battery as a serious safety concern, because it is completely unknown how and why it happened suddenly in the first place. The customer repeatedly discussed and/or emailed such concerns to both the dealership and Lexus Engagement Center staff on the same matter, only requesting to replace the “failed” battery with a new one. Both dealership and Engagement Center concluded no replacement can be done, only “continued monitoring” of the failed battery, citing Lexus protocols. However, the dealership service department also acknowledged there is no way for any customer to monitor this 12-V battery with either onboard displays or Lexus APP, as the 12-V battery condition is not being monitored by the existing Lexus software. Only another unfortunate incident or even fatal accident due to this “dead” battery could be the outcome of such “continued monitoring” and documented “repeated” failure. After that, they may be able to involve Lexus field engineering team to investigate it further.

2026 Lexus RX 350h Luxury AWD Hybrid. Component Affected: ELECTRICAL SYSTEM:12V BATTERY, DIGITAL/ELECTRONIC LOCKS I am experiencing a severe and persistent 12V parasitic battery drain on my 2026 Lexus RX 350h. The vehicle's auxiliary 12V battery drains completely to a dead state if left parked and unused for only two to three days. This is an ongoing manufacturing or software defect that prevents the auxiliary battery from maintaining an adequate charge, resulting in routine vehicle failure. Safety Risks and Incidents: This parasitic drain introduces several critical safety hazards: 1. Emergency Entrapment and Lockout Risk: Because this vehicle relies entirely on electronic door latches (e-Latch), a completely depleted 12V battery causes the exterior and interior electronic door release buttons to fail completely. This creates an immediate risk of vehicle entrapment or leaving passengers locked out in dangerous environments if they are unfamiliar with the secondary manual emergency release overrides.Stranding Hazards: The rapid, unpredictable nature of the battery depletion regularly leaves the driver stranded without warning in remote locations, dark parking areas, or during extreme weather conditions.Loss of Connected Safety Features: When the battery voltage drops severely before dying completely, critical connected vehicle safety systems—including automated emergency crash notifications, location tracking, and roadside assistance connectivity—are entirely disabled, presenting a severe risk in an emergency.Despite dealer awareness, battery replacements, and attempts to mitigate the drain, the manufacturer has not yet provided a permanent software or hardware fix to resolve this electrical defect. Yesterday, 8/31/2026 I took a 30 mile trip after fully charging the 12 V battery to 100%. Upon returning, I installed my battery maintainer. The maintainer stated 53% charge. The vehicle was not adequately charging while I drove. Vehicle software is malfunctioning.

The contact owns a 2026 Lexus RX 450h+. The contact stated that while occupying the vehicle, the battery lost power, causing the power door locks to fail to disengage and leaving the contact trapped inside the vehicle. Approximately 15 minutes later, the contact located the manual emergency release, unlocked the door, and exited the vehicle. The dealer was contacted and informed the contact of the manual emergency door release. The following day, the vehicle failed to start. The vehicle was towed to the dealer, but was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 1,000.

Technical Incident Timeline Suspected Unintended Acceleration Event 2026 Lexus RX 350h Premium+ (Approximately 96 Miles) Vehicle: 2026 Lexus RX 350h Premium+ Purchase Date: July 10, 2026 Dealer: Woodfield Lexus Incident Date: July 12, 2026 Approximate Time: 11:30 AM Vehicle Mileage at Incident: Approximately 96 miles ⸻ Event Sequence 1. Vehicle Startup * I entered the vehicle and started the vehicle normally. * The vehicle was in Park (P) at startup. * My right foot was on the brake pedal, as required to start the vehicle. * The accelerator pedal was not intentionally pressed. 2. Immediate Vehicle Behavior After Startup * Immediately after startup, the vehicle produced an unusually loud powertrain noise similar to a motorcycle engine. * The vehicle unexpectedly moved forward with strong acceleration without my intended input. * The acceleration was sudden and unexpected. 3. Loss of Vehicle Control * The vehicle traveled uphill at high speed. * The event occurred so quickly that I did not have sufficient time to react or take corrective action. * The vehicle became difficult to control during this period. * The front wheels climbed up the hill first. 4. Impact With Tree Trunk * The vehicle continued uphill and shortly thereafter struck a tree trunk. * After the impact, the vehicle changed direction toward the right. * The vehicle continued moving at high speed after the impact. 5. Attempt to Stop Vehicle * After the vehicle changed direction and continued moving, I recognized the need to stop the vehicle before it reached a concrete structure with a Jewel-Osco sign. * I applied the brake pedal again. * At this point, the brake responded and the vehicle stopped. 6. Resulting Damage * The collision caused significant damage to the vehicle, including damage to the driver’s side. * No warning lights or dashboard alerts appeared during the event.