C1391 on Toyota
Abnormal Leak of Accumulator Pressure (manufacturer-specific)
C1391 on Toyota vehicles indicates abnormal leak of accumulator pressure (manufacturer-specific). Au7o has documented this code across 2 Toyota models — most commonly on 4Runner, Camry. C1391 is a manufacturer-specific brake code, documented mainly on Toyota and Lexus (often hybrid) models, indicating the brake control system detected an abnormal leak or loss of accumulator pressure in the hydraulic ABS/brake actuator. The accumulator stores pressurized brake fluid the system uses for power-assisted and ABS braking, and degraded internal seals can let it bleed down. Because this directly affects braking assist and can increase stopping distance, it is a serious fault that should be repaired promptly by a qualified shop. Typical repair costs on Toyota range from $1,200 to $3,000, depending on the specific model and root cause.
Common Causes of C1391
- •Failing brake booster / master cylinder accumulator seals
- •Worn or leaking brake actuator assembly
- •Internal hydraulic leak in the ABS/brake actuator
- •Low brake fluid level
- •Aged or contaminated brake fluid
- •Faulty pump or pressure sensor within the actuator
- •Faulty brake control (skid control) ECU
C1391 on Toyota by Model
Toyota 4Runner(1 issue)
- Brake Booster / Master Cylinder Internal Leak Causing Hard Pedal and Reduced Braking Assist2003-2009
Multiple 4th-generation 4Runner owners report the brake pedal becoming hard, requiring excessive effort to stop, often accompanied by ABS/VSC/TRAC warning lights and a buzzing or continuously running brake actuator. Toyota issued service information for brake booster pump/master cylinder concerns on related platforms, and owner complaints frequently describe internal accumulator or actuator failure rather than simple pad/rotor wear. Repairs are expensive because the booster/master/actuator assembly is typically replaced as a unit.
Toyota Camry(1 issue)
- Brake Actuator / ABS Module Internal Failure Causing Warning Lights and Loss of Assist2007-2017
A well-documented issue on many Camry and Camry Hybrid models is failure of the brake actuator/ABS pump assembly, often accompanied by ABS, brake, traction, and master warning lights. Owners report the pump running frequently or continuously, a buzzing noise from the engine bay, hard pedal feel, and reduced brake assist. On hybrids, this can become especially expensive because the actuator and booster assemblies are complex and labor-intensive to replace.
Looking for C1391 on a different make?
View C1391 across all makes →Frequently Asked Questions
What does C1391 mean on Toyota?▼
C1391 stands for "Abnormal Leak of Accumulator Pressure (manufacturer-specific)." C1391 is a manufacturer-specific brake code, documented mainly on Toyota and Lexus (often hybrid) models, indicating the brake control system detected an abnormal leak or loss of accumulator pressure in the hydraulic ABS/brake actuator. The accumulator stores pressurized brake fluid the system uses for power-assisted and ABS braking, and degraded internal seals can let it bleed down. Because this directly affects braking assist and can increase stopping distance, it is a serious fault that should be repaired promptly by a qualified shop. On Toyota specifically, this code is documented across 2 models.
What causes C1391 on Toyota vehicles?▼
Common causes on Toyota: Failing brake booster / master cylinder accumulator seals, Worn or leaking brake actuator assembly, Internal hydraulic leak in the ABS/brake actuator, Low brake fluid level, Aged or contaminated brake fluid. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix C1391 on a Toyota?▼
Repair costs on Toyota range from $1,200 to $3,000, depending on the specific model and root cause.
Which Toyota models have C1391 documented?▼
Au7o has documented C1391 on 2 Toyota models: 4Runner, Camry.