P0556 on Cadillac: How to Diagnose & Fix
Brake Booster Pressure Sensor Circuit Range/Performance
1 Cadillac model · 1 documented issue · 1 critical
P0556 on Cadillac by model: symptoms, diagnosis and fix
The 2015-2017 Cadillac Escalade is included in GM safety recall 19V645000, which addresses a vacuum pump whose output may decrease over time. On the Escalade, that pump supplies the vacuum the brake booster uses to multiply your pedal input. As pump output falls, so does brake assist - the pedal gets heavy and the big SUV needs more room to stop. NHTSA describes the resulting risk as an increased chance of a crash. Owners should note that this is a distinct issue from mechanical brake complaints: the defect is in how much assist the system can deliver, and GM's fix is electronic. The recall covers 3,456,719 vehicles campaign-wide, spanning several GM full-size SUVs and pickups, not the Escalade alone.
Common Symptoms
- Brake pedal requires noticeably more force
- Vehicle takes longer to stop
- Power brake assist feels weaker than when new
How to Fix
Cadillac dealers perform the repair at no cost by reprogramming the Electronic Brake Control Module. The recall opened October 8, 2019; GM's campaign number is N192268490. Because the Escalade often changes hands early in its life, run the VIN through nhtsa.gov/recalls to see if the reprogramming is still outstanding, then reach Cadillac customer service at 1-800-458-8006 or your dealer to schedule it.
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 Cadillac?
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 Cadillac it is documented across 1 model: Escalade.
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 Cadillac?
Repair costs vary widely with the root cause and Cadillac model; each issue on this page carries its own estimate where one is published.
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.