C1256Brake accumulator pressure low

• Toyota/Lexus code · ABS / stability control
• Lights a warning lamp

How the car detects it

The pressure stored in the brake booster's accumulator is lower than it should be. On 2011-2015 Prius, Toyota lists it with C1252 and C1391 as a sign of an internal leak in the brake booster. Braking still works, but the brake assist may be reduced and the pedal can feel different. If the red brake warning light is on, have the car checked before driving further.

What you may notice

• Brake, ABS and/or VSC warning lights
• Pump running more often or longer than usual

Likely causes

• PossibleInternal leak in the brake booster / actuator
• PossibleBrake booster pump
• RareAccumulator pressure sensor

Sources

• purefjcruiser.com › 0280012.pdf
• toyota-club.net › br_ecb_6d.htm
• static.nhtsa.gov › MC-10158575-9999.pdf · official document
• static.nhtsa.gov › MC-11011632-0001.pdf · official document

Backed by an official manufacturer document.

From Obdaryn's Toyota/Lexus pack, exactly as the app shows it, with the public sources above. Guidance only; confirm with a workshop.