2012 Toyota Prius Fuel system Problems

While driving, the vehicle experienced a sudden brake system malfunction without prior warning or gradual degradation. The vehicle was being operated under normal driving, road, and weather conditions. No recent brake service, repairs, or aftermarket modifications had been performed prior to the failure. Multiple warning lights illuminated on the dashboard, including the ABS warning light, brake warning light, and traction control warning light. Shortly after the warning lights appeared, the vehicle began emitting continuous warning beeps. Audible buzzing or pumping noises were also present from the brake system during the malfunction. During this event, brake performance was reduced and braking felt inconsistent. The brake pedal became hard at times and spongy at other times, requiring increased effort to slow the vehicle and resulting in unpredictable braking response. This created a safety concern while the vehicle was in motion. The driver was forced to alter driving behavior and exercise extreme caution due to reduced braking confidence and unpredictable pedal feel. The malfunction has occurred intermittently during normal driving. The condition temporarily resolves on its own and later reoccurs without corrective action. The suspected failed component is the brake actuator / ABS actuator assembly. A diagnostic scan retrieved fault codes C1252 (Brake Booster Pump Motor ON Time Abnormally Long), C1253 (Pump Motor Relay Malfunction), and C1256 (Accumulator Low Pressure), which are consistent with brake actuator malfunction. The failure occurred at approximately 154,000 miles. This vehicle model and generation have a documented history of premature brake actuator failures with similar safety-related symptoms reported by other owners. The condition places the driver and others at risk due to unpredictable braking behavior, reduced braking effectiveness, and repeated warning alarms while driving. Warning lamps and audible alerts continue intermittently.

NHTSA ID

11707029

Incident

Dec 25, 2025

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.

NHTSA ID

11477997

Incident

Aug 6, 2022

I brought the car to the Toyota dealer already 3 times for the same problem,now happened again,they told me the first time,nothing wrong with the car,and I paid them,the second time nothing wrong they said,the third time they said it’s the 12 v battery has to be replace it,I did replace it,but still the same problem I have,the HYBRID SYSTEM problems ,the Toyota company should fix it ,because it’s something very unsafe it’s happening with my car,please help me to resolve this problem….. the car drive but stop anytime,I almost have a very bad accident with my daughter ON board

NHTSA ID

11453735

Incident

Feb 22, 2022

Hi, I have a 2012 Toyota Prius with around 120k miles that is completely inoperable. A local Toyota dealership is charging $3400 to replace both computers, but the more I research the more apparent it becomes that this is directly linked with past issues that were never fully resolved during previous recall attempts. The following article describes the exact situation my car is in (https://www.latimes.com/local/california/la-fi-prius-overheat-inverter-defect-20190414-story.html). When you combine that with the previous recalls back in 2014 & 2018, this quickly becomes a pattern. That pattern suggests that past software issues (1 & 2 below) were never fully resolved, and/or already caused premature damage to internal/computer components that then fail regardless. I spoke with the California Bureau of Automotive Repair who referred me to nhtsa. The agent I spoke with noted that because the Inverter wasn't actually replaced back in 2014 (Toyota only performed a software update), this part definitely could have been already damaged due to the software issues, which could then cause problems with the computers later on (which is what occurred). --- 1) NHTSA CAMPAIGN ID: 14V053000 - In the affected vehicles, the Intelligent Power Module (IPM) inside the inverter module (a component of the hybrid system) contains transistors that may become damaged from high operating temperatures. 2) NHTSA CAMPAIGN ID: 18V684000 - Excessive voltage in the Intelligent Power Module (IPM) within the inverter may cause the hybrid system to shut down, causing the vehicle to stall while being driven. --- General: - Computers both failed, not currently available for inspection as they are being replaced - If this computer failure happens again later (while on the road - as it has for other consumer), it's very dangerous as the car essentially shuts down on the spot - Dealer is dismissing this due to the car's age - No previous warning lights or messages

NHTSA ID

11450008

Incident

Jan 31, 2022

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.

NHTSA ID

11196480

Incident

Mar 24, 2019

Mileage

75,000 mi

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.

NHTSA ID

10860857

Incident

Apr 9, 2016

Mileage

31,703 mi

I WAS STOPPED AT A RED LIGHT ON A HILL. WHEN THE LIGHT TURNED GREEN, I STEPPED ON THE GAS WITH NO RESPONSE. THE CAR SLID BACK AND I BRAKED. THE PANEL LIGHT AFFIRMED THAT THE CAR WAS SUPPOSED TO BE IN DRIVE. YET THERE WAS NO RESPONSE AT ALL. THE CAR SEEMED TO BE IN NEUTRAL. I PUT THE BLINKERS ON AND THE CARS BEHIND ME PASSED. THE PANEL LIGHTS AND RADIO WERE ON ALONG WITH THE BLINKERS. I TURNED THE IGNITION OFF AND THEN TURNED IT ON AGAIN. IT WORKED WITHOUT A PROBLEM. I CALLED THE DEALER WHO STATED HE HAD NO IDEA WHAT HAPPENED AND THERE WAS NOTHING HE COULD CHECK. I HAVE DRIVEN THE CAR TO VARIOUS HILL TOPS AND STOPPED. THE PROBLEM DID NOT REPEAT ITSELF. IS THIS CAR SAFE TO DRIVE? IS THERE A WAY TO EVALUATE THE TRANSMISSION?

NHTSA ID

10717858

Incident

May 20, 2015

Mileage

20,500 mi

TL* THE CONTACT OWNS A 2012 TOYOTA PRIUS. THE CONTACT STATED THAT WHENEVER HE MADE A U-TURN, THE VEHICLE MADE A LOUD NOISE. THE VEHICLE WAS TAKEN TO THE DEALER. THE TECHNICIAN DIAGNOSED THAT THE FUEL SENDING UNIT NEEDED TO BE REPLACED. THE MANUFACTURER WAS NOT MADE AWARE OF THE FAILURE. THE VEHICLE WAS REPAIRED. THE VIN WAS NOT AVAILABLE. THE FAILURE MILEAGE WAS 15,000 AND THE CURRENT MILEAGE WAS 16,400. *TR

NHTSA ID

10507100

Incident

Jan 9, 2013

Mileage

15,000 mi

FUEL INDICATOR ON THE DASH SHOWED 3 BARS FOR REMAINING FUEL. VEHICLE RAN OUT OF FUEL DESPITE SHOWING 3 BARS. OFTENTIMES AFTER TANK IS FILLED IT ONLY ILLUMINATES TO 1 OR 2 UNDER THE TOP BAR INSTEAD OF SHOWING A FULL TANK. THERE IS OBVIOUSLY A PROBLEM THAT THE CAR IS NOT ACCURATELY REPORTING THE FUEL LEVEL. *TR

NHTSA ID

10478898

Incident

Sep 26, 2012

Mileage

13,104 mi

HYBRID ENGINE SUDDENLY SHUT DOWN WITHOUT WARNING WHILE VEHICLE WAS TRAVELING 65 MPH ON A BUSY FREEWAY, CAUSING VEHICLE TO COME AN UNSAFE STOP. DEPRESSING ACCELERATOR HAD NO EFFECT. ONBOARD COMPUTER GAVE ERROR MESSAGE "CHECK HYBRID SYSTEM. STOP THE VEHICLE IN A SAFE PLACE." RESTARTING VEHICLE PRODUCED THE SAME ERROR MESSAGE AND STILL UNABLE TO SHIFT VEHICLE INTO DRIVE OR REVERSE. FUEL TANK FULL AT TIME OF INCIDENT. VEHICLE PURCHASED NEW 5 MONTHS PRIOR FROM TOYOTA DEALERSHIP. NO AFTERMARKET PARTS OR MODIFICATIONS PRESENT. *TR

NHTSA ID

10472441

Incident

Aug 24, 2012

Mileage

9,550 mi

WHEN DRIVING DASHBOARD "HYBRID SYSTEM NOT WORKING. PULL OVER..." THIS WAS 7/3/2012. IT HAD RUN OUT OF GAS EVEN THOUGH THERE WERE 2 BARS OUT OF 10 STILL PRESENT ON GAS GAUGE. ON 7/30/12 LATER THIS HAPPENED AGAIN WITH 4 BARS SHOWING. GOT THE FUEL SENSOR AND GAUGE REPLACED ON 7/30/12. 8/14/12 WITH 3 BARS SHOWING, CRUISING RANGE OF 60 MILES AND HAVING GONE 480 MILES THE SAME WARNING "HYBRID SYSTEM NOT WORKING..." I WAS ABLE TO GET TO A GAS STATION BEFORE RUNNING OUT OF GAS. THE PRIUS MANUAL STATES THE TANK HOLDS 9.5 GALLONS. FILLING UP THE TANK TOOK 9.91 GALLONS. THERE IS CLEARLY SOMETHING WRONG. THE FUEL SENSOR AND GAUGE HAVE ALREADY BEEN REPLACED, THOUGH. THIS IS A MAJOR PROBLEM FOR A NEW CAR. THIS IS A NEW MODEL. *TR

NHTSA ID

10470699

Incident

Jul 3, 2012

Mileage

6,000 mi