2014 Toyota Prius V

Upon inspection, our mechanic determined that the master cylinder assembly and the actuator assembly require replacement (error code C1391). It is currently available for inspection, but will need to be repaired soon. Our safety and the safety of others is at great risk, because there is impending brake failure if driven and the end result could be catastrophic. On 09/13/25, the BRAKE, TRACTION CONTROL, ABS and ((!)) lights came on about 10 minutes from home. We drove home, parked the car and did not drive it again until we took it to our mechanic on 09/15/25. During this incident, the brakes failed to respond properly, which could have led to a serious accident. We took the car to a local mechanic and repairs are currently pending. The estimated cost for the necessary parts is approx. $3,000 and the labor costs are estimated to be between $1,100 and $2,000. Our local Toyota dealership was also contacted and they confirmed the presence of code C1391. Please reference Toyota Service Bulletin POL18-03, which addresses issues related to the braking system in certain Toyota models, including the Prius V. This bulletin indicates that various brake system-related warning lamps may illuminate due to internal malfunctions within the brake system, and it outlines affected parts that may require replacement. Additionally, please reference Toyota Customer Support Program 20TE07, which provides extended coverage for certain brake system repairs. It is concerning that, despite this well-known, very serious problem, Toyota has not issued a recall. While our vehicle currently has 116,975 miles, we are aware that the warranty period ended 10 years from the first date of use or 150,000 miles. However, this malfunction not only endangers our safety, but also that of other drivers on the road. We urge the NHTSA to investigate this matter thoroughly and consider the implications for a potential recall for this model, because Toyota is well-aware of this issue.

I have a 2014 Prius V with 92,000 miles. My anti-skid, brake and ABS idiot lights went off approximately 1 week ago. (August 25, 2025) Scheduled an appointment at my Toyota dealer (September 3, 2025) and was told there was an abnormal leak in the accumulator and that the brake booster pump and brake pump assembly needed to be replaced. Cost $5715. Not related to the brakes, but they also said I had to replace the rear shock absorbers as they are leaking and needed to be replaced and then realigned. Cost $1363. This should have been a recall not a mileage or 10 year limit.

Toyota has a break issue that they extended the warranty for 10 years or 150000 miles and now a few months pass the 10 years I have a problem with the actuator giving warnings and my daughter went into a skid when applying the breaks. She was lucky and didn’t hit anyone. If Toyota knows there is a problem that is a safety concern they should fix it I did get a Toyota dealership to give an estimate to fix it and was told $4300.00 I think that’s too much for a defective part. It should be a safety recall.

ABS Brake pump actuator booster failed. It is available for inspection. While driving, I started hearing a hissing sound from my brakes. I tried to slow down and my several diagnostic lights (ABS, traction control, brake, check engine, etc.) flashed on while my brakes failed to work properly. I turned on my hazard lights immediately. I was in the middle of the road with my toddler in the car and I almost rammed into the car in front of me. Luckily I was able to pull into a turn lane and pushed with all my might on the brakes and it finally was able to stop. My brakes failed and I could have hit the cars in front of me and hurt my child, myself and others. It was terrifying. Problem has been confirmed by an independent service center. The warning lamps only appeared WHILE the issue was happening and my brakes failed to work properly.

The car stalls randomly and does not enter fail-safe mode. The dealer says it is the transmission but the transmission has never shuddered or hesitated. I am reading that these vehicles have intelligent power modules in the hybrid inverter that fail and can cause stalling. I feel like the dealership is working with Toyota to avoid addressing the actual problem. In the meantime I was sent home in a vehicle that continues to stall randomly and does not enter fail-safe mode.

While braking on the interstate, this car threw error code C1391: Abnormal Leak of ACC PRESS. This is the brake system accumulator pressure - meaning lost all assistance to braking - it took a long time to slow down and come to a stop. Easily could have caused a serious crash had I been on a hill or coming up on stopped traffic. I did some research and found this is a KNOWN ISSUE with Toyota and SHOULD HAVE BEEN A RECALL! Toyota skirted the issue by offering customers that encountered the problem a CUSTOMER SERVICE PROGRAM where they would pay for a new brake pump and master cylinder. HOWEVER, Toyota put TIME and MILEAGE CONSTRAINTS ON THE PROGRAM, and it just so happened our car had exceeded those limits - so we had to pay full price for the repair of the 2 new brake parts - over $3,000! The 2014 Toyota PriusV that we bought new and had always serviced it properly was hardly worth that, but it was our only car, so we paid it. BUT will never buy another Toyota now - and NHTSA needs to fine Toyota for this poor brake system

Upon exiting the highway my brake system when engaged was completely unresponsive. I of course pushed down gently as would and upon realizing the brakes were not responding I started pounding on the brake pad. I had to ram the brake down for the vehicle to even slow. Thankfully no-one was in front of me at the light and I was able to pull into the nearest gas station having to ram brake to fullest extent to get the vehicle to stop moving. All lights within the braking system lit up including the Master Warning Light, Brake System Warning Light, ABS Warning light, and SLIP indicator as well as the warning siren. These warning lights did not come on til after* the brake system was engaged with failure*** NOT PRIOR. It was not indicative of an issue prior too, no former brake issue or warning lights. I turned the vehicle off and then back on again to see if the same lights still lit and issue was still malfunctioning. I called for a tow and had vehicle taken to the Adams Toyota Dealership (MO)The following diagnostic code C1391 was registered on my vehicle at dealership. Upon research (not disclosure) I found that the above code- C1391- "Brake booster and Brake Booster Pump Assembly" is a known issue that Toyota offered a Warranty repair from May 21-Nov 22' IF FAILURE Not a recall but a "if" brake system fails. Please see Customer Support Program 21TE01. I purchased vehicle in OCT 21 and was never informed, never provided this warranty letter, issue didn't show up on Carfax etc and I purchased directly from the Toyota Dealership. Upon research you will find that Toyota is currently in class action and individual lawsuits re this specific part failure with the above diagnostic code. They are denying replacement due the expired warranty time. The Parts should recalled* not just a "warranty issue" -unacceptable to leave buyers uninformed to such a major issue that can cause accident/death (IM PREGNANT I MAY ADD!) and unable to seek covered repairs unless it fails!

While driving my 2014 Prius V it stalled. I turned it off and restarted it. The yellow car symbol with an exclamation point lit up. I turned the car on and off again. The light went away and I was able to drive home. I was unable to get any OBD 2 codes on my personal reader. I changed the 12 V battery and thought this had fixed the stalling. Then it stalled again and repeated the same process. Though we were able to drove the car I had it towed to a dealership for safety reasons. The dealership pulled codes, cleared them, drove the car 20 miles, and were unable to reproduce the codes. I was told to return when the codes returned. It stalled again and now I am afraid to drive this car.