This is what Toyota is telling us on the diagnostic paperwork: Hydraulic Brake Booster Pump: DTC C1391 "Abnormal leak in accumulator" Has T-SB and CSP that are both expired. Recommend perform repair outlined. Recommend R&R Brake Actuator Assembly, booster Pump assembly and perform ABS ECU reflash.

First, we were never notified of this problem. Had we become aware of this problem when purchasing the vehicle we would not have gone through with this transaction. We don't have $4400 to repair this problem and we certainly don't have the funds to now go and purchase another car.

To add to this, we're told to just go ahead and drive and "watch the brake fluid and if brakes start to feel funny we should probably make a decision at that time". What kind of advice is this coming from Toyota????

There's existing problem occurring with 2010 Toyota Prius of mine, that braking is less responsive and also the ABS and side brake lamps are on the whole time on my dashboard.

My Mechanic friend found out that there's a problem with the Brake Booster Pump Assembly which can develop a crack inside the accumulator housing. If this occurs, nitrogen gas could leak into the brake fluid and gradually cause a loss of power assist. Under certain circumstances, this could affect stopping distance and increase the risk of a crash.

I took it to the Toyota dealer, but they claim there is no recall on my vehicle and charged $195 inspection fee and told me it costs over $2000-3000 repair the brake assembly . Why do we customers have to pay our own money that is almost the half a worth price of the vehicle to fix their defective design of their product!?

It is a life-threatening problem that is neglected by Toyota the defect of the brake booster kept occurring and resulted in brake failure.

Update from Aug 21, 2023: Subject: Urgent Report: Life-Threatening Brake Failure in the 2010 Toyota Prius

To Whom It May Concern,

I am writing to bring to your immediate attention a grave safety concern regarding the 2010 Toyota Prius. The braking system in this vehicle has become dangerously unresponsive, accompanied by the continuous illumination of the ABS and side brake lamps on the dashboard. This critical issue stems from a faulty Brake Booster Pump Assembly, specifically a crack developing inside the accumulator housing, causing nitrogen gas to leak into the brake fluid. The consequences are alarming: a gradual loss of power assist, compromised stopping distance, and an increased risk of life-threatening crashes.

Despite the urgency and potential for widespread harm, the Toyota dealer I approached shrugged off the severity of the problem, stating that no recall exists for my vehicle. Not only was I charged a steep $195 inspection fee, but I was also presented with a staggering repair estimate of $4,200—nearly half the value of the car itself. This raises a fundamental question: why should customers be burdened with the financial repercussions of Toyota's defective design?

I demand immediate action to rectify this life-threatening issue. It is imperative that the Bureau takes decisive steps to protect the lives of countless Toyota Prius owners. I urge you to:

1. Launch an urgent investigation into the recurring brake booster defects in the 2010 Toyota Prius models. 2. Enforce a mandatory recall of all affected vehicles, ensuring that the necessary repairs are conducted promptly and at no cost to the vehicle owners. 3. Hold Toyota accountable for neglecting the safety of its customers and demand appropriate compensation for those who have already incurred repair expenses.

This matter demands your utmost attention and swift action. Lives are at stake, and it is the responsibility of the Bureau to safeguard consumer interests and ensure the accountability of automobile manufacturers. I implore you to prioritize the well-being of Toyota Prius owners and take decisive measures to rectify this alarming situation.

I expect a prompt and comprehensive response outlining the actions you will take to address this urgent matter. Failure to act swiftly will not only compromise the safety of Toyota customers but also raise serious doubts about the Bureau's commitment to consumer protection.

Time is of the essence. Lives hang in the balance. I trust that you will act with the urgency and determination this critical situation demands.

Sincerely,

Kohtaroh Zushi

kohtarohzushi@gmail.com

I traded for this vehicle at a car dealership, drove it around the block, it drove well and didn't see any warning of what was fixing to be a major problem. I purchased the vehicle, drove it home and nothing unusual was going on. The next day I went to drive it, the Brake Booster Pump Assembly warning lights in the dash came on and would not go off. I called the dealership that I bought it from and they said that since I did not purchase an extended warranty with the car, that there was not much they could do. I told them that maybe I didn't purchase an extended warranty with the car but, I did not expect to have a major issue with the car two days after I purchased it. I would think that if something goes wrong with the car or I'm not satisfied with it, I would have 72 hours in which to take it back.

I researched the 2010 Toyota Prius and found out that there was a recall for the very issue I was having and that Toyota directed dealerships to repair the issue free of charge but... the recall was from March 2009 thru October 2009. However, I noticed another customer extension of the recall to November 2019. This does not bode well for me in my situation because I am 3 years past that date. I don't know what recourse I have now but, I continue to search for other information. I haven't written to Toyota North America yet but, I may have to. I really enjoy this car but, whatever happened to fair treatment under the law of good conscience and equity? I would expect bad treatment from a fly by night car dealer with 10 or 15 cars on the lot where you buy there and make your payments there but not from a reputable car dealership. Any suggestions would be appreciated as to what recourse I have.

Update from Dec 14, 2022: I just want to add that any suggestions for recourse to address this issue would be greatly appreciated as soon as possible, because the time of purchase and what I thought may be a 72 hour window to address my problem with the dealership is slipping away - and they may say I have had the car too long in order to return it or get it fixed. I might have to search for it but, I honestly thought that a customer has a 72 hour window to reject a purchase for cause. Thanks!

Upon starting the car one evening, brake, ABS and traction control lights all came on. Checked brake fluid and it was at max level. Took to dealer and diagnosed code 1391. It's a known failure of the brake booster and booster pump assemblies. Toyota had a voluntary recall out for this that expired in 11/19 or if under 150,000 miles. I'm less than 1,000 miles OVER that. Active recalls still open for 2011-2015 models.

How is it that they know about this for my 2010, had one and now won't cover this faulty part? It's a $3000 repair cost. This showed up on a vacation trip and we're also looking to have to have it towed to the repair shop because from research it seems unsafe to drive.