2015 Toyota Prius

The Office of Defects Investigation (ODI) has received a petition dated September 19, 2023 from the owner of a 2012 Toyota Prius V requesting that ODI reevaluate its decision to deny DP19-004. In the letter, the petitioner reported experiencing an unexpected and complete loss of brake power while driving, accompanied by multiple dashboard warning lights. This petition is based on the petitioner's direct experience and assessment that ODI closed DP19-004 because its prompting petition was withdrawn by that petitioner. ODI will review the work conducted during DP19-004 and a review of any additional related complaints and crashes via a new defect petition The petition and related materials can be reviewed at NHTSA.gov under the following ODI number:11553736.

NHTSA received a petition on or about July 18, 2022, requesting that Federal Motor Vehicle Safety Standard (FMVSS) 141 be applied to all electric and hybrid vehicles operating in the United States. The petition can be reviewed at NHTSA.gov under ODI Number 11486072. FMVSS 141 establishes performance requirements for pedestrian alert sounds for motor vehicles. The standard applies to hybrid and electric vehicles that have a gross vehicle weight rating of 4,536 KG or less or are defined as low-speed vehicles. The standard became fully applicable to all such vehicles manufactured on or after March 1, 2021.On January 27, 2023, NHTSA opened Defect Petition (DP) 22-005 to evaluate the subject matter described in the petition. On June 24, 2023 and as supplemented on June 25, 2023, the petitioner notified NHTSA he was withdrawing his petition. The petitioner indicated that, based on his review of data, there is no justification for asserting potential benefits that could be derived from actions sought by my petition. Based on the petitioner's withdrawal, DP22-005 is closed. Closure of this DP does not represent a determination by NHTSA regarding the subject matter of the petition.

On September 19, 2019, the Office of Defects Investigation (ODI) received a defect petition from Mr. Roger Hogan requesting that the Agency investigate and recall certain Toyota Prius, Prius PHV, Camry Hybrid and Avalon Hybrid vehicles for a brake actuator valve wear condition covered under Toyota Customer Support Programs ZJB and ZKK (subject CSP?s). In support of his request, the petitioner identified 117 NHTSA complaints allegedly related to the subject CSP condition, including 60 reporting crashes. On September 30, 2019, ODI opened Defect Petition DP19-004 to evaluate the petitioner?s request for an investigation. In August 2020, the petitioner notified the Agency that he was withdrawing his petition. Because the petitioner has withdrawn the petition, we are denying the petition as moot and no further analysis of this petition is necessary.NHTSA is authorized to issue an order requiring notification and remedy of a defect if the Agency?s investigation shows a defect in the design, construction, or performance of a motor vehicle that presents an unreasonable risk to safety. 49 U.S.C. ?? 30102(a)(9), 30118. Because the petitioner has with withdrawn the petition, the petition is denied as moot. This action does not constitute a finding by NHTSA that a safety-related defect does not exist. The Agency notes that it is not required to receive a defect petition prior to opening a defect investigation and will take further action if warranted by future circumstances.

I am reporting an active, severe safety hazard regarding the braking system on my 2015 Toyota Prius ( Mileage: 79,000). The vehicle has been officially diagnosed by Toyota Culver City with Diagnostic Trouble Code DTC C1391, confirming an internal failure and lack of pressure within the brake booster/actuator assembly. This component defect causes an immediate compromise to the vehicle's braking efficiency and hydraulic pressure, causing a sudden loss of braking power and significantly increasing stopping distances.Toyota was fully aware of this dangerous defect and initiated Customer Support Program ZJB to address it. However, Toyota Brand Engagement Center (Case #260909002032) has explicitly admitted via recorded voicemail that they mailed the safety/defect notification only to a previous owner and failed to notify me. Because they did not cross-reference current registration data, I was never notified of the defect and was deprived of a preemptive remedy before their arbitrary 10-year calendar clock expired. At only 79,000 miles, this critical safety component has failed prematurely, creating an active hazard on public roads. Toyota is refusing to cover the $3,890 repair despite their documented failure to notify the current owner.

NHTSA ID

11765138

Incident

Sep 7, 2026

Problem: Brake Actuator is pulsing the Booster Pump to keep running intermittently, 5-10 seconds. Console lights lit up for ABS problem. Does not clear. Toyota Dealership Report: DCT C1391 Abnormal Leak: Monitored TEH Accumulator Pressure and its not holding pressure. Pump keeps running. Rec[ommend] Brake Actuator and Booster Pump Assembly [replacement].` ServCo Toyota dealership in Hawaii Report: Submitted Prior Authorization request with Toyota Hawaii Warranty. Request Denied for Goodwill Coverage on ABS Actuator and Booster Pump.

NHTSA ID

11760825

Incident

Aug 23, 2026

On XXX, I was driving my 2015 Toyota Prius with my family in the vehicle and approaching stopped traffic on dry pavement. An emergency vehicle was approaching from behind, so I began braking earlier than usual. When I applied the brakes, the vehicle did not stop normally. The front slowed/stopped while the rear of the Prius suddenly slid sideways toward the adjacent lane, bringing the rear passenger side dangerously close to another vehicle. Had I begun braking at my normal stopping distance, I believe a collision would have occurred. No crash or injuries occurred, but the incident was extremely dangerous. I drove the vehicle very slowly to Purrfect Auto Services, [XXX], where the brake/ABS system was diagnosed. I observed diagnostic code C1391. The shop has had the vehicle since XXX and has experienced repeated problems with used replacement brake-system components that were defective or would not function properly. The vehicle has remained unsafe to return to service while the shop works to obtain a properly functioning replacement part. I am reporting this because the sudden and unpredictable braking behavior created a serious risk to my family and other motorists. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11759804

Incident

Aug 15, 2026

Code DTC C1391 - Abnormal leak of accumulator pressure. Internal failure of the brake booster pump assembly, preventing the system from maintaining proper hydraulic pressure. This means the brakes don't work, putting the driver's and passengers' lives at risk. This DTC C1391 code and problem were reproduced and confirmed by an independent service center who specializes in 3rd generation priuses. There were warning lights that lit up when the brakes failed - the ABS, traction control, and brake light all lit up but only after the brakes had stopped working. This is a known manufacturer defect but toyota won't pay to fix it because they put a 10 year limit on first driven date or 150,000 miles. This prius only has 100k miles but toyota still won't stand behind their product even though they have admitted it was a manufacturing defect and they sold a defective product.

NHTSA ID

11756229

Incident

Aug 6, 2026

I was rear-ended by a truck in my prius and my seat laid back on impact. I'm unaware if that was an intended thing or not but it potentially could have injured my neck. My car is currently in a storage lot awaiting the adjustor's inspection so it is available for inspection if needed. No warning lights were available and it hasn't been recreated by the dealer

NHTSA ID

11753382

Incident

Jul 27, 2026

Pulling out of a parking stall, when put vehicle in drive, the engine revved up and accelerated - vehicle crashed, the brakes did not work- there was skid marks. Floor mats are factory OEM were installed properly. I did not hit the accelerator and I am in good health and mind. I have driving for over 30 years, never had and accident nor a ticket! - A county officer was at the seen and left me with vehicle that had to be towed away. The Vehicle is a total loss. I have insurance but felt that this incident need to be reported, There is no safety recalls and the vehicle was always property maintained

NHTSA ID

11750516

Incident

Jun 28, 2026

The vehicle experienced a failure in the braking system involving the brake booster/brake actuator assembly. The vehicle displayed diagnostic trouble code C1391, which is associated with a malfunction of the brake booster pump/accumulator system on this model. The failed component is available for inspection upon request. The failure created a safety concern because the braking system warning lights illuminated and the vehicle’s brake assist system may not function properly. A malfunction of the brake actuator/booster system could increase stopping distance, reduce braking performance, and create a potential risk of a crash, especially during emergency braking situations. The problem has been confirmed through diagnosis showing the C1391 trouble code. The issue has been identified as a brake system malfunction requiring repair of the brake booster/actuator assembly. The vehicle has been inspected/diagnosed by a service professional. The vehicle has not been inspected by police or insurance representatives. Toyota/dealer inspection information is available if requested. I contacted Toyota regarding the issue, but they declined assistance because the extended warranty coverage expired approximately 7 months prior to the failure. Before the failure, the vehicle operated normally. The first symptoms occurred when multiple warning lights appeared while driving, including the ABS warning light, brake warning light, parking brake warning light (even though the parking brake was not engaged), and the traction control/slippery road warning light. These warning lights appeared suddenly, indicating a problem with the braking system.

NHTSA ID

11746503

Incident

Jun 23, 2026

The contact owns a 2015 Toyota Prius. The contact stated that while driving and coming to a complete stop, the vehicle was rear-ended by another vehicle driving approximately 35-45 MPH. The contact stated that upon impact, the front driver's seat unexpectedly reclined and struck the rear passenger’s seat. The contact was concerned about the movement of the seat and stated that an occupant seated directly behind the driver's seat could have been injured. The rear bumper, trunk, and rear body structure sustained damage from the crash. The contact stated that the force of the impact caused the rear driver’s side body panels to flare outward and become deformed. No additional property damage had occurred from the crash. The vehicle remained in the roadway following the crash. There was no warning light illuminated. The contact sustained neck injuries, whiplash, and emotional trauma from the crash. Medical attention was sought. The Uber passenger inside the vehicle was also transported from the scene to seek medical attention and treatment; however, the extent of the injury was unknown. The contact considered the vehicle a total loss by the contact, but the vehicle was not declared a total loss. The vehicle was towed to a tow yard. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 205,000.

NHTSA ID

11744174

Incident

Jun 10, 2026

Mileage

205,000 mi

OBSOLETE NOTICE February 13, 2026: This bulletin is now obsolete. Please see T-SB-0009-26.

This bulletin includes basic procedures for performing a rescue charge on Ni-MH high voltage (HV) batteries. This bulletin should be used in conjunction with the applicable model and model year Repair Manual while performing a rescue charge. The GRX-5100 should be used wherever the Repair Manual references the Toyota Hybrid System (THS) charger.

Some 2005 – 2026 Toyota vehicles that have undergone water intrusion may exhibit a condition in which a musty odor is present. Follow the procedures in this bulletin to remediate the odor and address this condition. The purpose of this Service Bulletin is to provide general guidelines and procedures for odor remediation. This Service Bulletin provides a guide on how to prepare and treat the interior of the vehicle for odor remediation. Refer to the applicable model and model year Repair Manual and the EPA (Environmental Protection Agency) website for the most up-to-date safety and precautionary guidelines.

The air conditioning dye injection tool kit has been developed to aid in identifying the location of air conditioning refrigerant leaks. The procedures outlined in this Service Bulletin aid in locating, inspecting, and repairing refrigerant leaks.

Acid rain results from rainwater or other airborne moisture that become acidic due to industrial chemical impurities in the atmosphere. If these acidic compounds settle on an exposed vehicle, especially the horizontal areas such as the hood, roof, and decklid, significant damage to the painted surfaces can occur. Acid rain damage can typically be identified on vehicles by the presence of stains on the paint surface that resemble hard water spots. Unlike water spots however, acid rain damage cannot be removed by regular washing procedures. Also, because acid rain can etch and soften the paint, normal buffing or polishing repair procedures should not be attempted. This can cause further damage and result in visible depressions in the paint surface. The following are the three major categories of acid rain damage: •Minor damage: requires only buffing to repair. •Moderate damage: usually requires neutralizing, color sanding, and buffing. •Severe damage: extending beyond 1/2 mil of clearcoat on a pearl, metallic, or solid color, requires neutralization, sanding, and repainting. In cases where acid rain damage is minor, neutralization and buffing with a liquid-type paint finessing product may provide an adequate repair. Only specially formulated products outlined in this bulletin should be used for that purpose. Unfortunately, other than minor damage, there is no simple method of determining the actual extent (depth) of acid penetration other than color sanding a representative affected area until there is no visible etching or depressions, followed by measuring the amount of paint removed with either a magnetic or digital-type film thickness gauge. The procedures in this bulletin are intended for use by qualified body/paint technicians and should not be attempted by inexperienced personnel. It is the dealer’s responsibility to protect and maintain the quality of the vehicle’s paint finish after receipt at the dealership prior to the first sale. Perform frequent vehicle washing, as often as daily, during high heat and humidity periods to minimize the potential for paint damage due to acid rain exposure. This is especially important in geographical areas known for high frequency and concentration of acid rain and industrial fallout.

To prevent brake rotor rust from forming during transportation and storage, wheel film will be used instead of a cardboard type of anti-rust cover. The purpose of the wheel film is to shield the disc brake rotor from weather elements and initial rust before the vehicle is delivered to the customer. Consequently, the film should remain on the wheel for as long as possible.