2012 Toyota Prius C problems

ELECTRICAL SYSTEM:PROPULSION SYSTEM:INVERTER

The contact owns a 2012 Toyota Prius C. The contact stated that while driving 20 MPH, the message "Check Hybrid Status - Stop vehicle in Safe Place Immediately" was displayed. There were several warning lights illuminated. The vehicle was towed to the local dealer, where it was diagnosed with an internal power module transmitter and MG control computer inside the inverter assembly failures. The vehicle was not repaired. The contact called an independent mechanic, and DTC: P0A94 (DC/DC converter or inverter performance problem invertor assembly) was associated with the failure. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 98,015.

NHTSA complaint #11722252 — an unverified report by a vehicle owner.

SERVICE BRAKES

While driving 65 mph on the expressway on January 12th, 2026 under cruise control, I tapped my brakes to slow down. My brake warning light came on, along with the ABS warning light, and the anti-swerve warning light. Cruise control no longer worked, and my brakes were noticeably hard to apply. I immediately had the vehicle computer checked and the issue is a leaking brake booster component, a faulty part known by Toyota to fail prematurely with this and other Prius models. No recall was issued however. The car is now unsafe to drive until a ~$4000 repair is done, according to my service representative.

NHTSA complaint #11712556 — an unverified report by a vehicle owner.

FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL

While driving 65 mph on the expressway on January 12th, 2026 under cruise control, I tapped my brakes to slow down. My brake warning light came on, along with the ABS warning light, and the anti-swerve warning light. Cruise control no longer worked, and my brakes were noticeably hard to apply. I immediately had the vehicle computer checked and the issue is a leaking brake booster component, a faulty part known by Toyota to fail prematurely with this and other Prius models. No recall was issued however. The car is now unsafe to drive until a ~$4000 repair is done, according to my service representative.

NHTSA complaint #11712556 — an unverified report by a vehicle owner.

SERVICE BRAKES

Brakes went soft with little braking power. Traced the fault code to a faulty braking actuator; toyota says this is past the coverage date for the recall.

NHTSA complaint #11707563 — an unverified report by a vehicle owner.

SERVICE BRAKES

I own a 2012 Toyota Prius C with approximately 156,578 miles. The vehicle has been diagnosed with C1391 – Abnormal Leak in Accumulator, which causes the brake actuator to lose hydraulic pressure. This results in frequent buzzing from the actuator pump, illuminated warning lights (BRAKE, ABS, Traction Control), and loss of ABS and stability control. The condition increases stopping distance and creates a serious safety hazard. Toyota previously acknowledged this exact defect under Customer Support Program CSP 21TE01, which covered brake booster and pump assemblies for certain Prius and Prius C models when codes such as C1391 were present. However, the program expired on November 30, 2022, and my vehicle is just over the 150,000-mile coverage limit. Despite this, my Prius exhibits the same defect that Toyota has already recognized as a safety-related issue. Toyota Carlsbad confirmed the diagnosis and quoted $3,399.55 plus tax for repair, with a reduced courtesy estimate of $2,817.86 plus tax, but declined goodwill assistance since CSP 21TE01 expired. Given the widespread reports of brake actuator failures in Prius models, I believe this represents a systemic safety issue that warrants NHTSA investigation and potential recall/extended coverage.

NHTSA complaint #11681477 — an unverified report by a vehicle owner.

SERVICE BRAKES

Brake Actuator and ABS Accumalator failed. It is a common failure reported by multiple owners on these cars. I was on the high way going 70 when it failed and lost any brake boost I had putting me in a very dangerous situation where I narrowly avoided an accident. Upon scanning the car's codes I got code C1391 which I looked up and saw a bunch of other people who were also struggling with this issue.

NHTSA complaint #11673785 — an unverified report by a vehicle owner.

ELECTRICAL SYSTEM

I am writing to express a complaint regarding the issues I have experienced with the brake system of my Toyota Prius C, 2012 model. For the past several months, I have noticed that the brakes exhibit strange noises, soft pedal sensation, reduced braking efficiency, were driving and the ABS, traction, brake, and that other light turned on and the brakes became slow these issues have been observed on multiple occasions and pose a safety risk to myself, other drivers, and pedestrians. I have taken the vehicle for inspection, but the problems persist or have not been definitively resolved. I believe these faults may be related to defects in the braking system, and therefore I request a thorough inspection and necessary repairs at no cost, considering that the manufacturer could be responsible for manufacturing defects.

NHTSA complaint #11664280 — an unverified report by a vehicle owner.

ENGINE

I am writing to express a complaint regarding the issues I have experienced with the brake system of my Toyota Prius C, 2012 model. For the past several months, I have noticed that the brakes exhibit strange noises, soft pedal sensation, reduced braking efficiency, were driving and the ABS, traction, brake, and that other light turned on and the brakes became slow these issues have been observed on multiple occasions and pose a safety risk to myself, other drivers, and pedestrians. I have taken the vehicle for inspection, but the problems persist or have not been definitively resolved. I believe these faults may be related to defects in the braking system, and therefore I request a thorough inspection and necessary repairs at no cost, considering that the manufacturer could be responsible for manufacturing defects.

NHTSA complaint #11664280 — an unverified report by a vehicle owner.

SERVICE BRAKES

I am writing to express a complaint regarding the issues I have experienced with the brake system of my Toyota Prius C, 2012 model. For the past several months, I have noticed that the brakes exhibit strange noises, soft pedal sensation, reduced braking efficiency, were driving and the ABS, traction, brake, and that other light turned on and the brakes became slow these issues have been observed on multiple occasions and pose a safety risk to myself, other drivers, and pedestrians. I have taken the vehicle for inspection, but the problems persist or have not been definitively resolved. I believe these faults may be related to defects in the braking system, and therefore I request a thorough inspection and necessary repairs at no cost, considering that the manufacturer could be responsible for manufacturing defects.

NHTSA complaint #11664280 — an unverified report by a vehicle owner.

SERVICE BRAKES

The brakes on this Prius started to make weird noises. Because it is a hybrid, I wasn't sure if it was normal. After searching online, it is a known issue. The car has just under 76,000 miles on it. It might be worth $7000 on a good day. Toyota wants to replace two brake parts, numbered 47050-52020 and 04006-74152 to a tune of $2700. According to a Toyota bulletin, this job should take 2.3 hours. For that amount of work, my local Toyota shop wants almost $2000 in labor. My car was seen by the local shop (being on an island, it is literally the only Toyota shop that this car can be seen) when the "customer support program" 21TE01 was in place and they did nothing. Now, the time window has disappeared, even though we only have half of the maximum number of miles to get the repair. Toyota should be ashamed of themselves.

NHTSA complaint #11643434 — an unverified report by a vehicle owner.

SERVICE BRAKES

My ABS actuator failed. Turns off the boosted braking and cruise control. This is a known issue in Toyotas and it always happens outside the warranty window. This is putting my safety at risk as the brakes don’t work as they’re supposed to

NHTSA complaint #11638598 — an unverified report by a vehicle owner.

SERVICE BRAKES

I was driving down the interstate with my cruise control on when all of a sudden the cruise control disabled and warning lights came up on my dash board. It still drove fine for several weeks. On Friday December 6th, I was going down the road and had to press the brake slightly for a car turning. When I pressed the brake, the car went into a spin. It spun a couple of rotations. Luckily I was on a wide part of the highway and no oncoming cars were approaching. Toyota had a recall for the same code and parts for the 2010 Prius but did not include the 2012 Prius. They just had an alert which I did not receive because the notice went to the former owner. However, I did take my car in for oil change and diagnostic but they did not tell me that there had been a problem with these parts. They want almost $4,000 to repair it. Why would they not include ALL vehicles with this same part. If it fail on one, it will fail on another. I think Toyota should make them all good. Please make them issue a recall for all of these parts. I took my car to a mechanic but because of special tools needed, you have to take your car to the dealership for repairs. When I called the dealership, I was told I needed a break booster pump and a brake master cylinder for a total of $3, which is ridiculous on a $7,000 car.

NHTSA complaint #11630042 — an unverified report by a vehicle owner.

ELECTRICAL SYSTEM

While my daughter was driving brake pedal faded and rear brakes locked up causing her to lose initial control of car . Steering felt tight . Many warning lights , check hybrid system , brake lights , steering warning lights , along with abs lights came on . Took car to Toyota dealer to diagnose it needs brake booster and master cylinder module . Service consultant said known issue with TSB but it had expired . Many , many complaints of this same incident of Toyota and Prius forums .

NHTSA complaint #11597788 — an unverified report by a vehicle owner.

SERVICE BRAKES

While my daughter was driving brake pedal faded and rear brakes locked up causing her to lose initial control of car . Steering felt tight . Many warning lights , check hybrid system , brake lights , steering warning lights , along with abs lights came on . Took car to Toyota dealer to diagnose it needs brake booster and master cylinder module . Service consultant said known issue with TSB but it had expired . Many , many complaints of this same incident of Toyota and Prius forums .

NHTSA complaint #11597788 — an unverified report by a vehicle owner.

SERVICE BRAKES

Code C1391 shows in which the accumulator and the brake booster assembly need to be changed. This is a known defect and was covered through an ‘extended warranty’ due to a lawsuit. Since it results in less than optimal braking, and can result in crashes since function disappears suddenly, it should have warranted a recall. This issue is also known to happen in multiple Toyota hybrid vehicles.

NHTSA complaint #11576687 — an unverified report by a vehicle owner.

SERVICE BRAKES

The brakes fail and the ABS module stops working correctly and when I go at a speed of 60 MPH the brakes lock until the speed drops and they work again. The problem is with the ABS module and I went to the dealer and the repair value is $3450 dollars.

NHTSA complaint #11549504 — an unverified report by a vehicle owner.

SERVICE BRAKES

Last week my 2012 Toyota Prius-C had four lights come on (ABS, Brake, Swerve, and one other). I took it to my local mechanic who informed me that it was my master cylinder brake that needed to be replaced and would cost me $3,300. This issue started roughly 10-12 months ago, when I heard my brakes making a noise that sounded very unusual, almost like a hydraulic issue. I learned that there was a Toyota initiated CSP. Toyota realized there was an issue with the 2012-2014 brake system that affected over 100,000 vehicles. Those affected by CSP's are supposedly notified by mail. Needless to say, I never received such notice. This aforementioned CSP expired in November 2022 that my car would have qualified for, had the problem been diagnosed prior. However, when I brought my car in on August 8th, 2022 for my hybrid battery, a diagnostic was done on my brake system with no indication that my brake system was in trouble. I really can't fault the mechanics at the local Toyota, I took it to a second brake specialist a few months after and they too could not identify the problem. The problem was so bad, Toyota discontinued the brake system. Toyota said it would need to be broken 100% with an error message to qualify prior to the November 2022 deadline. After being facetious and saying I should have broken the part myself to qualify, she said that is what I would have needed to qualify.

NHTSA complaint #11526268 — an unverified report by a vehicle owner.

SERVICE BRAKES

Without prior warning brake pedal goes to floor before minimally engaging braking system at a very reduced rate causing me to swerve and narrowly avoid collisions on interstate. There is no pressure feeling in the brake pedal although brake fluid level is normal and inspection of brake pads indicated significant pad available. No DTC light is coming on and OBD scan tool indicates no brake error. Brakes are unable to stop car to avoid collision, so car is dangerous and undrivable.

NHTSA complaint #11520747 — an unverified report by a vehicle owner.

UNKNOWN OR OTHER

My letter to Toyota: I'm writing this in regard to an inverter issue my 2012 Prius C recently experienced. While driving last month my car completely shut down, no warning and thankfully cars avoided hitting me and I was able to get from the middle lane to be able to coast to a side street in which I had to be towed. It turned out it was an inverter issue which had to be replaced. Granted my vehicle has less than 135k even though it is a 2012. I have done research and found models of Prius had the same exact issue(s) which was part of a warranty enhancement and I truly think my vehicle should be included. I want this to be looked in to and addressed. I will be contacting NHTSA also in regard to this. I filed with Toyota and ref#230323001904

NHTSA complaint #11513487 — an unverified report by a vehicle owner.

SEAT BELTS

Seatbelt does not retract or lock properly when braking.

NHTSA complaint #11512708 — an unverified report by a vehicle owner.

ELECTRICAL SYSTEM

I was driving on the expressway and experienced a sudden loss of power. The internal combustion engine suddenly stopped and did not deliver any power to the wheels. I immediately received a message on the system that said 'Check Hybrid System Stop Vehicle in a Safe Place'. The electric motor still continued to provide some power with the available battery charge. I was able to make it to the shoulder of the road but it was challenging to get to the shoulder with no power or warning and high speed traffic. My wife and I were in the vehicle. The vehicle had no engine or error codes until the failure on the expressway. The vehicle has the code P0A1A and P0A94. This is consistent with the error codes in the NHTSA 19V491000 recall and Toyota Safety Recalls E0E and F0R.

NHTSA complaint #11490716 — an unverified report by a vehicle owner.

ENGINE

I was driving on the expressway and experienced a sudden loss of power. The internal combustion engine suddenly stopped and did not deliver any power to the wheels. I immediately received a message on the system that said 'Check Hybrid System Stop Vehicle in a Safe Place'. The electric motor still continued to provide some power with the available battery charge. I was able to make it to the shoulder of the road but it was challenging to get to the shoulder with no power or warning and high speed traffic. My wife and I were in the vehicle. The vehicle had no engine or error codes until the failure on the expressway. The vehicle has the code P0A1A and P0A94. This is consistent with the error codes in the NHTSA 19V491000 recall and Toyota Safety Recalls E0E and F0R.

NHTSA complaint #11490716 — an unverified report by a vehicle owner.

UNKNOWN OR OTHER

I was driving on freeway when my vehicle shut off and wouldnt start again. It almost caused an accident thankfully not. I paid to have car taken tothe repair shop Viva Toyota in Las Cruces NM and they inspected it and gave me a quote on repair as well what was causing the problem. There was a saftey recall for the PCU and i believe the inverter is causing the failure. please help me to get this figured out.

NHTSA complaint #11484484 — an unverified report by a vehicle owner.

SERVICE BRAKES

a warning light came in on my dashboard brakes regarding the Brake pump accumulator. It feels like my brakes are not working right, not stopping like they always did.I was scared I almost hit someone in front of me at a red light because after applying the appropriate notes due on the brake pedal I noticed a delay in the car stopping. I had the brakes checked by a mechanic and they are ok. This is very dangerous. Can the manufacturer be required to repair this defect? Thank for your help.

NHTSA complaint #11457814 — an unverified report by a vehicle owner.

SERVICE BRAKES

My brakes gave out while driving with my infant child luckily I was almost home and made it without hitting anyone or seriously hurting myself and my child. Had car diagnosed error code c1256. Local dealership won’t repair because I “missed “ recall and my car has salvage title. I cannot afford to fix on my own and I’m shaking as I drive with my child to work everyday praying to get there in one piece because I have to work…

NHTSA complaint #11445845 — an unverified report by a vehicle owner.