2021 Toyota Sienna Hybrid

Unexpected failure of the acceleration pedal to accelerate from a complete stop to a go at an intersection. The electric vehicle (EV) motor began accelerating up to about 3 mph than instantly had a failure to accelerate, even with the gas pedal continuously pushed to the floor. After about 4 to 5 seconds the engine kicked on and began accelerating. The failure seemed to occur during the EV motor swapping over to the gas powered engine. This has been the fourth occurrence and can be extremely dangerous at intersections with oncoming traffic. No fault codes or check engine lights came on.

1. The rear underbody air conditioning (AC) lines and their supporting structural mounting brackets have failed due to severe corrosion. Specifically, a heavy steel mounting bracket has rusted excessively, causing localized galvanic corrosion at the point of contact with the adjacent aluminum AC lines. This structural and material failure caused the aluminum line to erode, crack, and leak high-pressure chemical refrigerant into the environment. The vehicle, failed components, and detailed photographic evidence of the galvanic corrosion and rusted bracket are fully available for inspection upon request. 2. The failure presents multiple safety and health hazards: •Environmental and Inhalation Hazard: The high-pressure leak of mobile air conditioning refrigerant (R-1234yf or R-134a) releases a hazardous chemical compound directly beneath the cabin. •Defrost and Visibility Failure: The rapid loss of system pressure completely disables the vehicle’s climate control and window defrosting/demisting capabilities, severely compromising driver visibility during inclement or humid weather. •Structural Degradation: The severe rust and erosion of the underbody mounting bracket mean structural components are failing prematurely on a 2021 model, creating a risk of loose or dragging underbody debris at highway speeds. 3. The physical failure (loss of refrigerant and severe physical corrosion) has been visually confirmed. However, the Toyota dealership service center actively refused to document the cause. However, photographic evidence clearly reveals the distinct, localized galvanic corrosion occurring exactly where the rusted steel bracket contacts the aluminum line. Further, Toyota’s highlander model had this same problem which was addressed through T-SB-0021-26. 4. The vehicle was inspected by an authorized Toyota dealership which acknowledged the leak but refused to provide a written technical breakdown. 5. Rust, corrosion, and loss of cooling ability.

My 2021 Toyota Sienna Hybrid has an intermittent and dangerous brake failure where the brakes suddenly release pressure during normal braking. When slowing down—especially at lower speeds or approaching a stop—the brake pedal briefly loses resistance and the vehicle surges forward as if the brakes let go. I must immediately re‑apply hard pedal pressure to avoid rolling into traffic or another vehicle. The vehicle as a result can stop up to six feet past the intended stopping point in some instances. This issue is unpredictable and has occurred multiple times. It creates a serious safety risk. Toyota performed T‑SB‑0047‑24 (Brake ECU Reprogramming) on my vehicle, whereafter the brakes seemed to function normally for several months, but the problem resurfaced and occurred threee time in one week in May of 2026, which prompted me to bring it backk to Toyota for another look. The dealer has been unable to reproduce the issue and therefore has not repaired it. The veicle has been returned to me, and continues to have the problem intermittently at a random frequency. Toyota corporate Brand Engagement Center has been notified, and a case was opened (Ref # 260528002416). This case was closed however after telling me that the dealership connot reproduce the problem, therefore they cannot repair it. This appears to be a brake control defect involving the hybrid brake‑by‑wire system. Because the failure is intermittent and leaves no diagnostic codes, it is extremely difficult for the dealer to diagnose, but the safety risk is severe. I'd like to advise that I have owned and driven earlier hybrid models (2012-14) that never exhibited this type of brake failure. I'd also like to point out... an internet search of this problem reveals that this problem seems to be prevelant in newer Toyota hybrid models. This was confirmed by the service manager at my local dealership. I have not been informed of any continuing engineering efforts given the failure of the TSB.

Both front struts of the vehicle have failed and are leaking. There is only 36,000 miles on this vehicle when they should last 200,000 miles per Toyota's service department. Toyota refuses to acknowledge this is their problem and that it's a "wear and tear' part. However clearly these parts should not fail after so little usage.

We were stopped at a stoplight. As soon as we stepped on the gas pedal, there was a loud clunk sound and plastic parts started flying out from under the car. We immediately pulled over. Oil was spilling out everywhere. The transmission oil pump was laying on the inside of the engine compartment. We had towed to Toyota. They diagnosed a bent piston went through engine which also caused a hole in the transmission. I had it towed for a 2nd opinion. Neither toyota or the 2nd opinion had ever seen anything like it. My mechanic also said there are a bunch of other suspension parts that were damaged due to the violent stop of the engine. There are a few of the same incidents online in chat rooms. The car is totalled and we are out of a car now.

The contact owned a 2021 Toyota Sienna Hybrid. The vehicle was parked in the driveway when an explosion occurred; the vehicle burned down. The contact was inside the residence when a loud noise was heard, and the house "rocked." The contact ran to the front of the house to investigate and noticed that the vehicle was engulfed in flames. The fire damaged the driveway, melted the garage door, and melted a landscaping retaining wall. The fire damaged the post on the front porch. The contact and her family were unable to exit through the front door due to the fire and used the sliding kitchen door to exit the residence. The fire department was called to the scene. Per the contact, three fire trucks were at the scene. The fire department informed the contact that the fire went up to 3,000 degrees. The fire department concluded that the fire started from underneath the driver's back panel. The contact stated that the gas tank was underneath that area and believed the gas tank may have contributed to the fire. The towing company towed the vehicle to a towing yard, and it was later picked up and towed to an unknown location. The insurance company was notified and declared the vehicle a total loss. The manufacturer was made aware of the failure and advised the contact that an inspection was needed on the vehicle and asked for the location of the vehicle.  However, the contact was awaiting the results. The failure mileage was approximately 80,000.

The contact owns a 2021 Toyota Sienna Hybrid. The contact received notification of NHTSA Campaign Number: 23V865000 (Air Bags). Upon contacting the local dealer, the contact was informed that the parts for the recall repair were on backorder. The contact had not experienced a failure related to the recall. The manufacturer had not been contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair.