2012 Toyota Prius: sudden loss of power

Filed Jan 25, 2026 · Brakes · MO

Vehicle: 2012 Toyota Prius Mileage: Approximately 217,000 miles While driving normally in traffic, the vehicle experienced a sudden and unexpected brake system failure. Multiple warning lights illuminated simultaneously, including the red BRAKE warning light, ABS warning light, traction control light, and warning symbol (!). Shortly after, the vehicle began emitting an audible warning/beeping, and there was a sudden loss of power brake assist. The brake pedal behavior changed abruptly: the pedal became very soft initially, then became suddenly hard halfway through travel, This failure occurred while approaching another vehicle in traffic, and I narrowly avoided rear-ending the vehicle in front of me. The unexpected loss of brake assist created an immediate and dangerous situation, as the vehicle did not decelerate as expected when the brake pedal was applied. Due to the seriousness of the brake failure and safety risk, the vehicle was removed from service and towed. This incident represents a critical safety defect, as sudden loss of braking assist while driving poses a significant risk to vehicle occupants and other road users. I am reporting this incident to document the hazard and request investigation into the reliability and safety of the brake system design. I am requesting you to please issue a recall and reimburse me , as these parts are very expensive , it affected my financial situation, Thanks

Filed Nov 6, 2025 · Electrical · NC

The hybrid system fails to enter “Ready” mode with no SMR engagement audible from the junction box. Dashboard displays ABS, brake, engine, and master warning lights. OBD codes include U0142, U0155, and previously U0073 . Rear brake lights function normally when pedal is pressed. Dealer said to pay 250$ for diagnostic and diagnosed incorrect voltage from brake light switch and quoted $348.94 to replace, but refused to proceed with open safety recall J0V / 18V684 (the federal safety agency 18V684000) citing inability to achieve “Ready” mode. Recall covers inverter failure leading to loss of motive power. Dealer declined to jump 12V battery or use external power to perform required software update and inverter inspection. Vehicle remains inoperable and poses safety risk due to sudden power loss potential. Component (inverter G9200-47141) available for inspection. Problem confirmed by dealer diagnostics. No police or insurance inspection. Warning lamps appeared after 12V battery replacement three months ago.

Filed Aug 7, 2022 · Fuel system · OR

I was driving my 2012 Prius on the highway at around 55 MPH. The Hybrid System Warning came on and the car lost all power and immediately began to coast. I was fortunate not to have been in or caused an accident but cars behind me had to swerve to avoid hitting me. I was able to coast to a middle median lane. After waiting 15-20 minutes, the car never regained power. We were finally able to push it off the road and into a parking lot. It never regained power.

Filed Dec 26, 2019 · Transmission · 87,000 miles · NC

Vehicle was in motion traveling about 50 MPH when an effort was made to pass another vehicle on a 2 lane road, the vehicle lost power while we were passing, we barely got back into our lane and just barely avoided a head on collision. Then the vehicle slowed to about 15 MPH and limped to a stop a mile later. We could have died.

Filed Apr 15, 2019 · Engine, Fuel system · 75,000 miles · IL

Soon after getting a recall software update for the hybrid system, the car displayed hybrid system check message and lost power. Car had to be towed. Created an extremely dangerous situation due to nature of problem while driving on the road and had to pull over right away.

Filed Jan 29, 2019 · Engine · 203,079 miles · TX

I went to the charles maund toyota dealer at austin, tx for a recall. The federal safety agency recall id 18v684. According to the official recall remedy from the federal safety agency, "if the vehicle has experienced an inverter failure with certain hybrid system faults related to this condition, the inverter assembly will be repaired or replaced free of charge." my car lost power on the highways several times recently. The error code is p0a08, which is related to inverter failure with certain hybrid system faults, so the inverter assembly should be repaired or replaced free of charge. But the dealer didn't want to replace or repair the inverter for my car. There is still a potential threat on my car to lose power on highways.

Filed Apr 22, 2016 · Fuel system · 31,703 miles · CA

I was driving the 2012 prius on a downhill parkway at about 40 MPH when the warning light check hybrid system came on. Within 10 second, the vehicle totally lost power. It automatically shifted into neutral. There was no back up fail-safe/limp home mode. Fortunately the car was gliding downhill by gravity and eventually was steered into a driveway. Then it refused to go on ready or drive mode. On this saturday afternoon the car had to be towed home. It had to be towed again to the dealership for service the following week. It took the mechanic two days to make a diagnosis that a fuse on the main drive battery had blown. Another day was spent waiting for the part. The dealership cannot guarantee that this event will not happen again. I contacted toyota USA. An agent named michael was courteous enough to listened to me and gave me a case number 1604142245. To anyone with common sense, this total lack of an emergency alternative propulsion system for even a cheap car is unacceptable. The dealership cannot even come up with a plausible explanation as to what may have caused the fuse to blow. Was it over heating? Was there a short in some internal battery cells? This past week, I noticed that the charging part of the operation no longer can fully charge the battery to the former 11.9 mile range. It only charges up to 9.8 miles. This is a sudden loss of 2 miles of charge. I suspect that some lithium cells have been damaged after the incident. I also suspect that there may be other issues as well such as something wrong with the inverter module related to a recall on other models of prius during my search for an answer. I need assurance from someone that this vehicle is now safe to drive. Besides the case number from my complaint to toyota USA, aaa has record of my recent towings on 04/09/16 and on 04/12/16.

Filed Nov 18, 2013 · Airbags, Lights · 27,000 miles · CA · crash

My 2012 prius was hit in back on passenger side at approximately 80-85 miles/hour while my speed was 62 m/h. With impact from hit in the back, my car went flying head on into the median wall (those temporary cement walls used during reconstruction). Two things happened were: 1. After the first impact my prius had total power loss, not even emergency flasher light would turn on; 2. Non of airbags deployed. I am wondering if all this is normal for this car or there is some sort of malfunction or manufacturing defect?

Filed Sep 7, 2012 · Acceleration, Electrical · 4,944 miles · CA

Driving 70 MPH car began to go into high RPM, then accelerated to 74 from 70 MPH. I tried to decrease speed then vehicle shut off got a long beep and message on display "check hybrid system, pull over immediately" all lights on dash were indicating failures. Coasted to safety with 5 passengers in vehicle across traffic at 9:30 pm to shoulder. Tried to restart several times then vehicle went into high RPM then engine knocked loudly and was completely disabled. Lost brakes, pedal was hard, lost power steering, difficult to maneuver. I still had 2 bars indicating plenty of fuel in car. Prior fillup was 7.6 gallons at pump, usually get over 500 miles per tank, trip meter only showed under 400 miles since fill up so had plenty of fuel and there was no low fuel indicator. Reported all problems to dealer. They only noted the car shut down but told me they confirmed everything I said and that toyota engineers are trying to resolve this since they are aware of this type of problem. So far dealer and toyota have not addressed the high RPM, the acceleration, loss of electronics and hybrid system failure and told me they havenever heard of any toyota ever having a report of a high RPM or acceleration without intent to accelerate form the driver. Vehicle is unsafe, has 4944 miles and this problem occurred about a month after purchase. Toyota still does not know what the problems are and in possession of the vehicle. *tr