2015 Toyota Prius: ABS light or ABS activating

Filed Nov 7, 2026 · Brakes · MS

Abs, traction light on , and brake light on and the brake is not working good. Need to press it hard to apply brake . It happen with out a reason.i called toyota when i have a recall for that but they refused because it dont have any light sign on it but still it make a loud buzzing sound all time time when car runs and brakes also feels spongy .now recall is expired i have to replace by my self

Filed Aug 31, 2026 · Brakes · HI

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.

Filed Aug 26, 2026 · Brakes · NV

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)

Filed Aug 11, 2026 · Brakes, Driver assistance · CA

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.

Filed Jun 25, 2026 · Brakes · CA

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.

Filed Jun 9, 2026 · Brakes, Electrical · GA

The incident involved having to press extremely hard on the brake pedal to stop the car, while it was uphill in the middle of the road. The car started going backward and was throwing ABS, Master Warning Light, Brake System Warning Light and Warning Buzzer, Brake System Warning Light, and SLIP Indicator signals. This was a highly distraughtful situation on the road. Diagnostics showed C1391 Diagnostic Trouble Code on the 2015 Toyota Prius: brake booster and brake booster pump problem. When pressing the brake pedal there is a high pitched metal scraping noise. Toyota coverage program is only applicable for 10 years from the date of first use or 150,000 miles, whichever occurs first. Many cars run well for over 10 years with good care, so the 10 year cap barely covers anything. This is highly unfair and borderline scamming for an issue so severe, which can cause big accidents on the road. In all honesty, this is a life or death situation when it comes to not being able to properly brake while driving. This should be a full recall!!

Filed May 26, 2026 · Brakes · CA

I was driving my 2015 prius for years and occasionally the brake, abs and traction light would come on this is a sign of a failing Brake actuator and booster. Toyota and the Ntsb ordered the following warranty enhancement My Brake Booster had been exhibiting signs of failing for years and I tried to get a toyota dealership to replace and repair the parts under the warranty extension but I was told I had to wait until I had perminent dash lights and trouble codes. So I had to wait till the booster completely failed. By that time my car had exited the extended warranty perimeters and I am told it is no longer eligible.... even though the components are faulty from the factory and exhibited signs of failure many years prior. I was told to wait until the compenent failed by multiple dealers. My car was in motion and the brake boosters failed, fortunatly it did not cause an accident but this is a serious safety issue. Toyota should have done a compleat recall of the brake actuator and booster pump, rather than have drivers use known faulty components until failure. Toyota corporate has refused to help in the repair of the vehicle despite it showing failure for years.

Filed May 10, 2026 · Brakes · CA

Toyota Prius has a known problem with the brake actuator and booster. A notice was sent out in 2019 under the Customer Support Program Expansion with repairs up to 10 years or 150k miles. This is a safety issue and should be covered under a recall with NO TIME OR MILEAGE LIMITS since these problems are not showing up until after 10 years if the car has low mileage, as in our case. We just passed the 10 year mark, but only has 114k miles. No mention of repairs needed were made during regular maintenance visits with Toyota. Additionally, preventative repairs were not offered if the vehicle did not seem to be experiencing problems at that time. The brakes are spongy and unresponsive. The ABS light , traction warning lights, and parking brake lights are staying on.

Filed May 7, 2026 · Brakes · CA

ABS braking system suddenly not working. ABS, BRAKE, and traction control lights all turned on.

Filed May 6, 2026 · Brakes · CA

On 4/16/26, while driving my 2015 Toyota Prius (approximately 87,000 miles) on the freeway, I applied the brakes while transitioning from the [XXX] onto the [XXX] . As I veered right on the curved onramp, the brakes failed to engage properly, causing the vehicle to spin out of control and collide with the side railing. There were fortunately no nearby vehicles on the 2-lane onramp at the time. Under slightly different circumstances, this incident could easily have resulted in serious injury or death to myself and/or others. No airbags deployed. Although I was physically unharmed, I was extremely shaken by the incident. Immediately after the collision, the brake warning light, ABS warning light, and another warning indicator illuminated on the dashboard. Prior to the incident, I had not experienced braking problems severe enough to suggest imminent failure. On 4/17/26, I brought the vehicle to Toyota of Cerritos for diagnostic evaluation. I was informed that the brake booster was the issue and that the vehicle was unsafe to drive. The vehicle was towed to a collision repair center affiliated with my insurance company. After repairing the external collision damage, the collision center informed me that the brake booster malfunction that caused the incident could not be repaired there and would require dealership service. External repair alone: $3706, in addition to increased automobile insurance premiums expected over the next 3 years. I also contacted Toyota Motor Corporation regarding Customer Support Program coverage related to brake booster issues and was informed that the program expired in 2025 and no assistance would be provided. I am submitting this report because this brake booster malfunction created a serious and unexpected safety hazard resulting in loss of vehicle control on a freeway interchange. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Mar 20, 2026 · Brakes, Driver assistance · LA

In June 2025, while driving on the highway, the vehicle suddenly displayed multiple brake warning lights and warning messages, including the red brake warning light, ABS light, brake system warning light, and traction/slip indicator. At the same time, the brake pedal became stiff and braking effort increased suddenly, creating a near-crash situation because the vehicle did not slow normally. Before that incident, the vehicle had already been making abnormal brake-related noises, including a humming/pumping noise when the brake pedal was applied, and there were intermittent episodes where braking felt abnormal. In June 2025, the vehicle was taken to a Toyota dealership during Toyota’s brake booster support program period. The dealership documented customer complaints of “humming noise in cabin when holding foot on the brakes,” a request to “scan for codes for ZJB enhancement,” and that the “vehicle hard to accelerate and brakes got stiff,” but stated that no qualifying ABS codes were present at that time. In March 2026, the same condition returned and worsened. The vehicle again displayed the red brake warning light, ABS light, brake system warning light, and traction/slip light, and braking performance was reduced. An OBD scan of the ABS control unit showed code C1391, which is associated with brake booster / ABS actuator failure. The Toyota dealership has now diagnosed the vehicle with ABS actuator and brake booster failure and quoted repair. This is a serious safety issue because braking became more difficult while driving, including on the highway, with sudden warning lights and degraded stopping ability. The failed components are available for inspection. The problem has now been confirmed by a Toyota dealership. The issue was reported to a Toyota dealership during the prior support-program period but was not confirmed then.

Filed Mar 20, 2026 · Brakes · CA

Brake Booster and ABS, Brake Master Cylinder went out in car without any lights or warning while driving the vehicle at a moderate speed on Freeway. I was able to avoid an accident and take the car to a repair shop in which at 119K miles and just at 10.5 yrs old the entire brake system had to be replaced/repaired.