P0556 on Ford: How to Diagnose & Fix
Brake Booster Pressure Sensor Circuit Range/Performance
1 Ford model · 1 documented issue · 1 critical · $300-$800 repair
P0556 on Ford by model: symptoms, diagnosis and fix
The vacuum pump that provides brake assist on EcoBoost F-150s can fail, resulting in a hard brake pedal and reduced braking assist. Since turbo engines don't produce intake vacuum like naturally aspirated engines, they rely on this pump.
Common Symptoms
- Hard brake pedal
- Increased stopping distance
- Brake warning light
- Whining noise from pump area
- Reduced brake assist
How to Fix
Replace vacuum pump. This is a safety-critical repair - do not drive with failed pump. Check for diagnostic codes related to brake booster. Inspect vacuum lines for leaks as well.
Sources for this issue (1)
P0556 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 P0556 mean on a Ford?
P0556 stands for "Brake Booster Pressure Sensor Circuit Range/Performance." The brake booster pressure sensor signal is present but out of the expected range or implausible relative to operating conditions. A range/performance fault. On Ford it is documented across 1 model: F-150.
What are the most common causes of P0556?
The most common causes of P0556 are: Faulty brake booster pressure sensor, Vacuum leak at the booster or hose, Wiring resistance / poor connection, Failing vacuum source / pump, Faulty PCM input. The specific cause varies by vehicle.
How much does it cost to fix P0556 on a Ford?
Published repair estimates on Ford range from $300 to $800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0556 on a different make?
View P0556 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.