C0561 on Ford: How to Diagnose & Fix
System Disabled Information Stored
1 Ford model · 1 documented issue · 1 critical
C0561 on Ford by model: symptoms, diagnosis and fix
The brake master cylinder rear cup seal can roll or fail, allowing brake fluid to leak from the front-circuit reservoir into the brake booster. This drops fluid in the front brake circuit and can reduce or eliminate front-wheel braking (rear brakes remain). Drivers report a long/soft pedal traveling near the floor, a brake warning light, and a low reservoir often with no visible external leak. The defect has driven repeated recalls on 3.5L EcoBoost trucks — 16S24/16V-345 (2013-2014), 20S31/20V-332 (2014-2017), 22S11/22V-150 (2016-2018), and 25S37/25V-236 (2017-2018) — and caused documented non-injury crashes.
Common Symptoms
- Brake pedal sinks toward the floor
- Increased pedal effort / hard pedal
- Red brake warning light and low-fluid chime
- Reservoir repeatedly low with no external leak
- Reduced front braking, longer stopping distance
How to Fix
Have the VIN checked for open recalls (16S24, 20S31, 22S11, 25S37) — the master cylinder is replaced free of charge, and the brake booster is also replaced if it shows evidence of fluid contamination. Outside recall coverage, replace the master cylinder (and booster if soaked). Do not ignore a recurring low reservoir or any change in pedal travel/effort; this is a loss-of-braking safety condition.
Sources for this issue (3)
C0561 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does C0561 mean on a Ford?
C0561 stands for "System Disabled Information Stored." This code sets when the ABS/electronic brake control module disables itself because it received invalid, missing, or implausible serial data over the vehicle communication bus. Rather than a failed brake part, it usually means the module can't trust the data it's getting from another module (or the bus itself is faulty), so it shuts down ABS and stability/traction control as a precaution. Common subcodes include -71 (invalid serial data received) and -72 (alive counter incorrect, indicating a bus or sending-module problem). The driver typically sees ABS, traction, and 'Service Stability/StabiliTrak' messages while base braking still works. On Ford it is documented across 1 model: F-150.
What are the most common causes of C0561?
The most common causes of C0561 are: Communication (CAN/serial data) bus fault or corrupted data, Failing module on the bus sending bad data, Wiring or connector problems on the data lines, Corrosion at module connectors, Low battery voltage or charging problems, Body control module or other module fault, Software/calibration mismatch between modules. The specific cause varies by vehicle.
How much does it cost to fix C0561 on a Ford?
Repair costs vary widely with the root cause and Ford model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.