Forward Collision AvoidanceService BrakesUnknown Or Other
The traction control, abs, and emergency brake light came on. We checked and the code produced was C1391. There’s a humming noise every 10 or so seconds when idle. The humming noise is also present when braking. We did some research and this appears to be an issue with Toyota Prius. We called the dealership and were informed tha…
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The traction control, abs, and emergency brake light came on. We checked and the code produced was C1391. There’s a humming noise every 10 or so seconds when idle. The humming noise is also present when braking. We did some research and this appears to be an issue with Toyota Prius. We called the dealership and were informed that this was not a known issue. Thank you.
NHTSA ODI #11748069
Mileage unknown · Jun 1, 2026
Forward Collision AvoidanceService Brakes
ABS, traction control, brake system, and brake lights turned on while driving. Took the car to the mechanic and pulled the code C1391. It seems from other complaints to NHTSA that it is a common issue and quite dangerous, meaning the brake system is failing.
The brake system malfunctioned suddenly. While driving and while stopped, the brake pedal became very hard and braking behavior became unpredictable. The vehicle sometimes brakes aggressively and other times requires excessive pedal force to stop. The ABS and BRAKE warning lights illuminated. The vehicle no longer provides norm…
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The brake system malfunctioned suddenly. While driving and while stopped, the brake pedal became very hard and braking behavior became unpredictable. The vehicle sometimes brakes aggressively and other times requires excessive pedal force to stop. The ABS and BRAKE warning lights illuminated. The vehicle no longer provides normal braking assistance. This issue is related to a failure of the brake actuator / brake booster, which is a known issue affecting Toyota Prius models from 2010 to 2015. This defect creates a serious safety risk, as braking performance is inconsistent and may increase stopping distance or cause loss of control during emergency braking situations. The vehicle has not been repaired yet because the cost is very high and the manufacturer has declined assistance despite this being a known safety-related defect.
NHTSA ODI #11707101
Mileage unknown · Mar 22, 2025
Forward Collision AvoidanceService Brakes
Failed Brake booster and pump assembly, confirmed by Toyota service. Warning lights turned on all at once: AEB, skid control and brake light. Estimated cost to repair is $3,000.
NHTSA ODI #11649889
Mileage unknown · Mar 10, 2024
Forward Collision AvoidanceService Brakes
Code C1391 - Abnormal Leak in Accumulator. Accumulator for the brake pump is not holding pressure so the pump has to keep turning on to refill. Brake pump and ABS unit have to be replaced. In emergency situations, a malfunctioning ABS module leads to increased stopping distances and loss of steering control during hard braking.…
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Code C1391 - Abnormal Leak in Accumulator. Accumulator for the brake pump is not holding pressure so the pump has to keep turning on to refill. Brake pump and ABS unit have to be replaced. In emergency situations, a malfunctioning ABS module leads to increased stopping distances and loss of steering control during hard braking. Lastly, tires can be worn more easily, which could lead to tire blowouts. This puts myself and others at risk for deadly consequences due to an increased chance for collision if I am unable to control or stop my car. This problem has been confirmed by Toyota and multiple years of Toyota vehicles have had their brake actuator assembly warranty enhanced. The warranty enhancement program has secondary coverage, which is applicable for 10 years from the first date of use, or 150,000 miles, whichever occurs first. Currently I meet the 10 year requirement but have 162,000 miles on my prius, which is completely frustrating. Many have posted with the same problem of being just outside the warranty. The vehicle has been inspected at a Toyota dealership. A symptom was noticeable starting from over 1 ½ years ago when I was under 150,000 miles. The car produced clicking sounds when the brake pedal was held down at traffic lights. Once released, the clicking sound would stop. I spoke with a Toyota mechanic and he told me it was an issue with the brake pump and ABS unit, but Toyota would not repair it until it completely failed. He also mentioned that there was coverage available for the ABS unit once it failed as it was a common issue for the Toyota Prius. If Toyota warranty allowed for the brake pump and ABS unit to be replaced when the symptoms appear instead of when it completely fails, I would have qualified with my mileage. Not only is the repair costly, but for those who cannot afford it and need to continue to use their car despite the brake pump and ABS unit failure, risk their own and others safety when continuing to operate their vehicle.
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2013-2015 Prius and 2014-2017 Prius V vehicles not included in recall 18V-684. Excessive voltage in the Intelligent Power Module (IPM) within the inverter may cause the hybrid system to shut down, causing the vehicle to stall while being driven.
Consequence & remedy
Consequence: An unexpected hybrid power system shut down may increase the risk of a crash.
Remedy: Toyota will notify owners, and dealers will perform a software update for the hybrid system. If the vehicle has experienced an inverter failure with certain hybrid system faults related to this condition, the inverter assembly will be repaired or replaced, prior to software update. All repairs will be performed free of charge. This recall began July 24, 2020. Owners may contact Toyota customer service at 1-888-270-9371. Toyota's number for this recall is 20TB10 / 20TA10.
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2010-2014 Toyota Prius and 2012-2014 Toyota Prius V vehicles. Excessive voltage in the Intelligent Power Module (IPM) within the inverter may cause the hybrid system to shut down, causing the vehicle to stall while being driven.
Consequence & remedy
Consequence: If the hybrid system shuts down unexpectedly, it can increase the risk of a crash.
Remedy: Toyota will notify owners, and dealers will update the software for the motor/generator control electronic control unit (ECU) and the hybrid control ECU as necessary, free of charge. The recall began January 22, 2019. Owners may contact Toyota customer service at 1-888-270-9371. Toyota's number for this recall is J0V. Note: The software updates in this recall are needed even if the vehicle had the software previously updated under recalls 14V-053 or 15V-449.
Toyota is recalling certain model year 2010 through 2014 Prius vehicles. In the affected vehicles, the Intelligent Power Module (IPM) inside the inverter module (a component of the hybrid system) contains transistors that may become damaged from high operating temperatures. If this occurs, various warning lamps will be illuminated on the instrument panel and the vehicle will have reduced power allowing it to only drive a short distance.
Consequence & remedy
Consequence: The vehicle may enter a fail-safe/limp-home mode that limits the drivability of the vehicle. The hybrid system could also shut down completely resulting in a vehicle stall, increasing the risk of a crash.
Remedy: Toyota will notify owners and dealers will update the software for both the motor/generator control electronic control unit (ECU) and the hybrid control ECU, free of charge. If an owner experiences a failure of the inverter before the vehicle receives updated software, the dealer will repair or replace the inverter assembly with a new one at no charge. The recall began on March 21, 2014. Owners may contact Toyota at 1-800-331-4331.
Additional source detail variants (2)
Hybrid Propulsion System: Inverter
Toyota is recalling certain model year 2010 through 2014 Prius vehicles. In the affected vehicles, the Intelligent Power Module (IPM) inside the inverter module (a component of the hybrid system) contains transistors that may become damaged from high operating temperatures. If this occurs, various warning lamps will be illuminated on the instrument panel and the vehicle will have reduced power allowing it to only drive a short distance.
Consequence: The vehicle may enter a fail-safe/limp-home mode that limits the drivability of the vehicle. The hybrid system could also shut down completely resulting in a vehicle stall, increasing the risk of a crash.
Remedy: Toyota will notify owners and dealers will update the software for both the motor/generator control electronic control unit (ECU) and the hybrid control ECU, free of charge. If an owner experiences a failure of the inverter before the vehicle receives updated software, the dealer will repair or replace the inverter assembly with a new one at no charge. The recall began on March 21, 2014. Owners may contact Toyota at 1-800-331-4331.
Electrical System:software
Toyota is recalling certain model year 2010 through 2014 Prius vehicles. In the affected vehicles, the Intelligent Power Module (IPM) inside the inverter module (a component of the hybrid system) contains transistors that may become damaged from high operating temperatures. If this occurs, various warning lamps will be illuminated on the instrument panel and the vehicle will have reduced power allowing it to only drive a short distance.
Consequence: The vehicle may enter a fail-safe/limp-home mode that limits the drivability of the vehicle. The hybrid system could also shut down completely resulting in a vehicle stall, increasing the risk of a crash.
Remedy: Toyota will notify owners and dealers will update the software for both the motor/generator control electronic control unit (ECU) and the hybrid control ECU, free of charge. If an owner experiences a failure of the inverter before the vehicle receives updated software, the dealer will repair or replace the inverter assembly with a new one at no charge. The recall began on March 21, 2014. Owners may contact Toyota at 1-800-331-4331.
Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗
NHTSA investigations
3
DP23005 · Brake Actuator Valve Wear
Opened Nov 22, 2023 · No close date supplied
Status: open (inferred from source dates) · Service Brakes, Hydraulic:foundation Components; Service Brakes, Hydraulic:power Assist
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.
Additional source detail variants (2)
Service Brakes, Hydraulic:foundation Components
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.
Service Brakes, Hydraulic:power Assist
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.
DP22005 · Pedestrian Alert Sounds
Opened Jan 27, 2023 · Closed Aug 7, 2023
Status: closed (inferred from source dates) · Electrical System:propulsion System
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.
DP19004 · Brake Actuator Valve Wear
Opened Sep 30, 2019 · Closed Jan 21, 2021
Status: closed (inferred from source dates) · Service Brakes, Hydraulic:power Assist
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.
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