Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC C1B6E Accumulator Pressure Stuck: Notes
1. -
DTC detecting condition:
Accumulator pressure sensor output value does not change even if the pump motor operates, and this condition continues for 14 seconds or more.
Trouble symptom:
- Brake cannot be controlled.
- Regenerative brake cannot be controlled.
- Brake assist does not operate.
- EyeSight functions (ACC/PCS) do not operate.
- CHECK DTC
.
- Using the Subaru Select Monitor, perform the clear memory of [Electric Brake Booster]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
- Turn the ignition switch to OFF.
- Turn the ignition switch to ON, depress the brake pedal 10 times or more to make the pump motor operate.
- After the pump motor stops, read the DTC of [Electric Brake Booster] using Subaru Select Monitor. Ref. to ELECTRIC BRAKE BOOSTER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC C1B6E displayed?
Yes: Replace the brake booster assembly (with the master cylinder). Ref. to BRAKE>BRAKE BOOSTER .
No: Currently, it is normal. Temporary interference from noise is a possible cause.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.