CODE C1391 - Brake booster assembly failure

- Upland, CA, USA

Last year, the brake light failure came on the dashboard. I brought the car to a repair shop they diagnosed the problem as a rusted brake line on the passenger side. Bill approximately $700 for the repair. Over the last weekend, I was driving near my home, and the same indicator lights came on. I drove home and when I got home, noticed that there was brake fluid on my garage floor. I checked the brake fluid level there was none detected. I filled it up with brake fluid and waited until the next day, and the level seemed stable. I started the car to bring it to a local repair shop. No more indicator lights were showing. The repair shop said it was the driver's side brake line that had rusted out. $400 for it to be replaced. I reported this to Toyota today. Reference Number #250516001403

- Mayfield Heights, OH, USA

Brake accumulator suddenly failed in vehicle. Known issue from manufacturer

- Chula Vista, CA, USA

Vehicle warning lights for brakes, ABS and traction control all on while driving. Per mechanic, known problem on Prius and repair cost is $3-$5K. Covered by a prior customer support program but has expired. I have two Prius-??s with the identical problem - bill will be up to $10K. Error code C1391

- San Diego, CA, USA

Vehicle warning lights for brakes, ABS and traction control all on while driving. Per mechanic, known problem on Prius and repair cost is $3-$5K. Covered by a prior customer support program but has expired. I have two Prius-??s with the identical problem - bill will be up to $10K Error codes C1391, C1214

- San Diego, CA, USA

the abs booster/master cylinder has failed due to an internal leak causing the accumulator pump to constantly run and sets a c1391 dtc. the brakes work poorly and has a stiff pedal feel. braking is definitely reduced. this issues has not been seen by any dealer, shop, or agency yet. I was a toyota certified Master Diagnostic Technician for years before i quit to be a stay-at-home dad and am more than qualified and capable to accurately diagnose this. in addition, toyota has a CSP out (ZGB) that covers this, but the coverage needs to be extended. this is a known very dangerous failure that should be covered for much longer. i did notice, what i thought was an over-frequent cycling of the accumulator pump, but since i had just purchased the vehicle, it was hard to tell how out of the norm it was.

- Concord, NC, USA

CODE C1391 for leak in brake accumulator pressure. All brake system lights flashed (e-brake, traction control, ABS).

- Seattle, WA, USA

The brake booster pump assembly has been failed.everytime I tried to stop the. vehicle the brake pedal will go to the floor and it will take longer to stop the car. IT has been inspected by my mechanic and conformed the problem

- Louisville, KY, USA

failure of the brake booster system resulting in no ABS function, appears to be a common problem with this vehicle.

- Shoreacres, TX, USA

The abs system and brake lights started showing on my dash and when I put my foot on the brake it makes a noise and the car shakes hard to brake when to the mechanic they said is the abnormal leak acc pressure code c1319

- Woodland Hills, CA, USA

The brake booster assembly (part number 47070-47060) on my 2013 Toyota Prius has failed. This component is critical to the proper functioning of the braking system. It is currently still installed in the vehicle and available for inspection upon request. As a result of the failure, the ABS warning light, traction control light, and brake warning light are all illuminated on the dashboard. The braking performance has noticeably declined -?" the pedal feels inconsistent and at times unresponsive. This has created a significant safety risk while driving, especially during sudden stops or in wet conditions, as it compromises the vehicle's ability to brake efficiently and predictably. The issue has been confirmed by a Toyota dealer (or independent mechanic if that-??s the case -?" feel free to change this line accordingly). The dealer diagnosed the issue as a failure of the brake booster assembly, which aligns with known failures reported by many other 3rd-generation Prius owners. The vehicle has not been involved in an accident, and has not been inspected by the police or insurance representatives. Toyota previously issued a Customer Support Program (CSP ZJB or ZG1) covering this part, but it has since expired. I only recently began experiencing symptoms and was unaware of the CSP until after contacting Toyota. Prior to the warning lights, I experienced intermittent symptoms such as a soft or delayed brake pedal, and an unusual sound from the brake system when the vehicle was turned off. The warning lights first appeared around [insert approximate mileage or date here], and have remained illuminated since then. Given the safety-critical nature of this component and the known defect history, I am requesting assistance from Toyota in the form of goodwill coverage or reimbursement, and would like this issue escalated for further review.

- Fremont, CA, USA

ABS, Brake, and Traction Control light came up had dealer review these and got error code C1391 and P0441. Initially they said its covered by Toyota customer service program which covered upto 150k miles as my vehicle only has 98k miles. Later they said only 10 years from the vehicle service which ended in 2023 and quoted $4500 to fix. Previously i asked them to check before expiration since it was not showing consistent light on they could not fix it. Reading through several forums it seems like consistent issue should have been included in recall not customer support program.

- Windermere, FL, USA

While driving on the highway at ~70 mph, the brakes just gave out and I narrowly escaped crashing into someone as I drove into the median having been unable to stop in the expected distance. The ABS light just came on and apparently it-??s a very known issue that Toyota is refusing to fix or intimate owners. I have been going to the same dealership for 12+ years and never had this brought up by them.

- Edmond, OK, USA

Was driving on the freeway and 3 dash lights lit up. found out the brake accuator is failing. apparently this is a known issue for toyota priuses.

- Anaheim, CA, USA

It was raining when I drove my 2013 Prius to pick up my daughter from school on March 11, 2025. I suddenly felt the brake of the car was very weird, it was hard to stop at the stop sign, and when I stepped the brake paddle I had to make more effort to control the car to stop. The brake light and ABS light were both on. I drove the car to the local dealer next morning they said the brake booster with master cylinder & pump assembly need be replaced, and it was cost over $4000. I did research and found it was a common problem for Prius but Toyota did not do a recall, instead the customer repaired program has expired on 2023. It is very dangerous for this situation.

- Hemet, CA, USA

The brake actuator has stopped functioning properly in my 2013 Toyota Prius that has 124,000 miles. NHTSA is welcome to inspect my car. I took my car to a Toyota Service Center because of a noise that cycles every 15 seconds. The mechanic said the noise "is in fact coming from the accumulator of the brake boosters." He said it's kind of like a battery--it may go out tomorrow or next year and it would be $3,957 for the job, but recommended to wait until it completely goes out. I was shocked he said this when I later read online this is a very dangerous problem that should not be ignored and should be fixed right away. I learned that Toyota issued an extended warranty for this known problem yet my car is not eligible because it's been more than 10 years. No warning lamps or messages have appeared. I'm afraid to drive my car and would never have bought it if I'd known how frequently this happens in this generation of Prius. I can't even sell it in its current state because no one will want to pay a $4,000 repair cost.

- Round Rock, TX, USA

Failure of ABS module and actuator..Known problem with Prius

- Mt Juliet, TN, USA

Toyota did a voluntary recall on the brake booster pump on this particular model when I inquire at the dealership about it they said that it has expired and refuse to fix the recall issue I did not know a recall can't have an expiration date especially when it can cause an accident

- Roanoke, VA, USA

The brake booster and ABS system failed requiring replacement of the entire system. A Toyota dealer service center examined the vehicle and deemed it unsafe to drive until the repairs were made. It was held for months due to part availability.

- Norman, OK, USA

A well documented issue on the brake booster and master cylinder developing leaks and requiring replacement effecting Gen 3 Prius models well before the parts should show such issues. known to toyota under customer support program ZJB but arbitrarily limited by VIN batches and time span leading to me and it seems many others being hung out to dry

- Franklin, NC, USA