2026 Toyota Bz

SUPPLEMENT TO ODI COMPLAINT 11758090 (filed 8/19/2026). Two corrections, an identified component, and a verified manufacturer remedy. Full narrative attached. CORRECTIONS. (1) The prior 12V battery was replaced 5/29/2026, not June 2026; invoice 569207 is correct. (2) The complaint attributed the drain to an armed charging schedule. That was a proxy, not the cause. The trigger is ANY vehicle wake -- key-fob approach at ~8 ft, end of drive, or converter pulse -- which arms a timer of exactly 180 minutes, after which a 0.87-0.9 A sawtooth discharge runs 4.6-9 hours, consuming up to 12 Ah. Verified 8 of 8 events 8/8-8/23/2026 by amp-hour shunt and independent voltage logger, one pre-registered in advance and correct to the minute. The defect is not avoidable by any owner setting. REMEDY. 8/24/2026, Cavender Toyota, repair order 604263, under Toyota Technical Assistance System case TA262360433: ignition off; vehicle removed from owner's Toyota app garage; ignition on 1 min (pending telematics upload completes); off 1 min; on; vehicle re-added to app garage. No parts, no charge, ~10 minutes. The procedure operates only on the DCM/connected-services registration state, which identifies the component. VERIFICATION. Two deliberate fob wakes 8/24 (19:25, 23:10 CDT): no discharge at 180 minutes or overnight. Twelve days of normal use through 9/5/2026: zero events. TOYOTA'S OWN RECORDS CORROBORATE. The TAS advisory tells the technician to "set up for 3 hours to monitor," matching the measured 180-minute latency. Invoice 593644 records the 12V battery needing 2.5 hours of external charging. The TAS case records "Dealer Visit: 4," escalation reason "Multiple Repair." The dealer's 8-day monitoring (7/28-8/5) found nothing because a vehicle parked in a service lot is never woken: 1 mile accrued in 8 days. No recall or TSB communicates this remedy; case TA262360433 remains open, "Vehicle Repaired" blank. Full instrumented record available to ODI on request.

The 12-volt auxiliary battery system repeatedly discharges itself and has twice left the vehicle completely inoperative: 7/24/2026 (5.58 V at the battery, parked unplugged ~46 hours after the last drive) and 7/28/2026 (5.95 V, failure during an attempt to enter READY to drive). The 12V system controls the contactors connecting the high-voltage traction battery to the drive system; when it collapses the vehicle cannot be started or driven even though the traction pack holds charge. The dealer replaced the 12V battery under warranty in June 2026; failures continued, so the battery was not the cause. I instrumented the 12V system with two independent cross-validated meters (precision current/amp-hour shunt; voltage logger sampling every 2 minutes) and measured the mechanism over 12 continuous days (Aug 8-19, 2026). Findings: (1) A drain event begins exactly 3 hours (180 min, within one 2-minute sample, in all six measured events) after the most recent vehicle wake - a READY cycle or the key fob merely coming within detection range of the parked car. Each new wake restarts the 3-hour countdown. (2) The event draws ~0.87 A; four completed events ran 4.6-4.7 hours (~4 Ah each), one ran 9.2 hours (~8 Ah). (3) Events occur with all charging schedules verified off in both vehicle and phone app, the app closed, and the vehicle unplugged. (4) The vehicle never replenishes the 12V from the traction pack while parked, and undercharges it when driven (13.9 V ceiling, single 30-minute window). Ordinary daily use - driving, parking unplugged, or walking near the car with the fob - drains the battery to collapse within days. No owner setting prevents it. A 6-day dealer observation did not reproduce it because the vehicle sat undisturbed: no wake, no drain. No warning lamps preceded either failure. Instrumented logs attached; vehicle and data available for inspection on request.

The 12 volt battery exhibits a consistent parasitic drain. This is intermittent, but results in the vehicle failing to start. The failure to start is an issue because it is happening frequently and could endanger individuals who live in rural areas or areas with cold or hot climate. This issue has happened to us multiple times and Toyota has not recalled or provided guidance to its dealer service network. Many effected owners have a diagnostic data backed theory that links the drain on the 12 volt battery to Toyota digital communication module. That diagnostic can be found here. Toyota should be forced to investigate and fix this as it is a big safety concern for those who are in rural harsh climates! It is impacting a lot of new BZ & CHR owners, but has been a known issue with previous models and even covered by some media outlets. Because this is a parasitic drain there often isnt a low battery warning before the car won't start. Another reason this deserves attention.

The vehicle suffers from an overnight parasitic 12V battery drain caused by a continuous cloud activation/software communication loop involving the Data Communication Module (DCM) and telematics system. The vehicle has gone completely dead and required jumping on three separate occasions. The issue was inspected and documented on a service invoice by an authorized dealership, which confirmed the battery itself tested good and recommended disconnecting the mobile application link due to the DCM cloud activation causing battery depletion. The recurring dead 12V battery creates a safety hazard by leaving the vehicle completely inoperable and stranded without warning.

Vehicle experienced a catastrophic, terminal 12V auxiliary battery parasitic drain that flatlines the system to 0% while parked, creating a severe safety risk by stripping hazard lights and motive power. This is the 3rd identical electrical collapse within 4 weeks; a late June 12V battery replacement failed. The vehicle was in active daily use, not stored.Held out of service at Kings Toyota since July 6, 2026 (26+ days down). Technicians dismantled the cabin and placed the dashboard in the trunk to trace loops. Management confirmed hardware nonconformities in the Data Communication Module (DCM) and Body Control Module (BCM), which fail to enter sleep mode. Observable proof includes continuous, erroneous telemetry alerts stating windows are down/doors unlocked while fully locked and disassembled in the bay.Modules are on indefinite global backorder due to an inherent manufacturing defect. Parts are restricted likely to feed production and the mass rollout for NHTSA Campaign 26V393.DIAGNOSTIC DETAILS:Local tech efforts are directly guided by Toyota Corporate factory engineers who designed the vehicle, as local techs have never encountered this severe issue.Multiple other identical units are grounded on the dealer lot with identical 12V flatline failures.My vehicle (#XXX) is being used instructively by Toyota Corporate to advance understanding and map out repairs for the other units.To capture evading data, I complied with a request to delete the Toyota app from my iPhone so lead tech [XXX] could intercept these failing module notifications to aid factory engineers.Management confirmed that by design, if the 12V drops below 11V, the high-voltage motive battery is supposed to automatically recharge it. Here, the vehicle fails to initiate the loop, or the motive batteries enter a defensive "protective lockout mode," cutting power transfer and flatlining the car. This could contribute to motive battery failure /lockout if the defect continues to draw 12V battery down. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INF

Vehicle purchased late March. Since then, the 12V gets completely drained to 0% over the weekend. This is a biweekly problem. Vehicle taken to dealership, they were not able to replicate problem. Dealership claims battery and vehicle perfectly fine. 12V battery continues to get discharged. This issue puts the customer at risk of being stranded on trips. No warning lamps or symptoms before battery dies making vehicle completely inoperable. Research online and owner forums clearly show a large number of owners having the same issue with this defect with this vehicle. Contacted toyota and they denied vehicle glitch or resolution. Toyota instructed me to take car back to dealership for them to address.

I am writing to formally advise Toyota Customer Relations of significant, unresolved performance and safety issues regarding my 2026 Toyota bZ, purchased new on February 14, 2026. Despite having only 976 miles on the odometer, this vehicle is currently demonstrating a battery state of health (SOH) of 82.7% and a maximum range of only 140 miles at 100% charge—even in moderate 40-degree temperatures. Description of Technical Failures: Battery & Range: The vehicle provides a maximum range of 140 miles at full charge. On an 80-mile roundtrip commute, I am forced to drive without cabin heat to ensure I can return home without a mid-trip recharge. Internal diagnostics currently show an 82.7% battery health, which is unacceptable for a vehicle less than a month old. Regenerative Braking: The regeneration system is not functioning properly, failing to recoup energy as designed. Infotainment & Safety: I have experienced consistent Bluetooth disconnections, audio drops during calls, map freezing, and—most concerning—the screen blacking out and resetting while the vehicle is in motion. Social Media Documentation & Peer Reports: Due to the persistent nature of these issues, I have documented my experience on the official "Toyota bZ (2026)" Facebook owner groups. My post has received numerous responses from other owners experiencing similar defects, suggesting a systemic issue rather than an isolated incident.