C1391 on TOYOTA PRIUS
Brake actuator accumulator pressure leak or ABS actuator fault
Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.
Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).
Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.
What C1391 Means on Your TOYOTA PRIUS
C1391 on Toyota Prius points to brake actuator accumulator pressure leak or abs actuator fault. FixIt matched 218 NHTSA owner reports for this exact code/vehicle pair, so use this page to prioritize the most likely symptoms, components, and next checks before replacing parts.
Real TOYOTA PRIUS Owner Reports
Source: NHTSA Complaints Database
"MY ABS BRAKE WARNING LIGHT CAME ON TWO DAYS AGO ALONG WITH ANOTHER BRAKE LIGHT. IT HAPPENED WHILE I WAS DRIVING SO IT WAS SCARY. I TOOK IT TO THE DEALERSHIP AND THEY SHOWED TWO CODES - C1256 AND C1391. THESE WERE PART OF A BRAKE ACTUATOR ASSEMBLY TOYOTA TECHNICAL SERVICE BULLETIN WHICH EXPIRED ON 12/31/2017. SINCE MINE"
"ABS WARNING LIGHT ARE NOW ON. FEEL CAR IS LOSING BREAK CAPABILITY. NO ACCIDENT BUT DO NOT FEEL CONFIDENT WITH THE BRAKE CAPACITY. TODAY I TOOK THE CAR TO THE DEALER AND THEY STATED THAT THE ABS ACTUATOR ASSEMBLY (CODE C1391) NEED TO BE REPLACE. LOOKING IN THE INTERNET AND IT LOOKS A VERY COMMON DEFECT FOR PRIUS. THIS I"
"MY VEHICLE HAS A DEFECTIVE ABS ACTUATOR, A PART PREVIOUSLY UNDER RECALL BY THE MANUFACTURER-TOYOTA. (2006 TOYOTA PRIUS ABS PART, ACTUATOR COMPLETE ASSEMBLY, ID 44510-47050) WARNING LIGHTS: MASTER WARNING ABS BRAKE SYSTEM: CODES: P0571, C1256, C1391. THIS DEFECTIVE BRAKING COMPONENT MAKES MY VEHICLE EXTREMELY UNSAFE TO"
"Loud grinding noise coming from engine compartment accompanied by a loud shrill alert. When attempting to pull over to a safe place, I put my foot on the brake pedal, but immediately became distressed because it felt like I had no brakes at all. After applying extreme pressure to the brake pedal, the car did begin to s"
"BRAKE ACTUATOR FAILURE. TSB RELEASED IN 2017. MY VEHICLE WAS OVER STATED MILEAGE LIMIT (150,000), AND WAS NOT SHOWING ANY ILL EFFECTS OF THE 2017 TOYOTA REPAIR AT NO COST. I AM DRIVING ALONG US 77 AND ON THIS 4 LANE MAJOR HIGHWAY, THE POWER ASSIST BRAKES FAIL. NOW 204780 MILES 5/2019 AND THE EMERGENCY BRAKE, ABS,VSC AN"
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on TOYOTA PRIUS
Based on NHTSA complaint component analysis for this vehicle.
What To Do Next
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1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
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2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
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3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.