P0556 on Cadillac
Brake Booster Pressure Sensor Circuit Range/Performance
P0556 on Cadillac vehicles indicates brake booster pressure sensor circuit range/performance. Au7o has documented this code across 1 Cadillac model — most commonly on Escalade. The brake booster pressure sensor signal is present but out of the expected range or implausible relative to operating conditions. A range/performance fault.
Common Causes of P0556
- •Faulty brake booster pressure sensor
- •Vacuum leak at the booster or hose
- •Wiring resistance / poor connection
- •Failing vacuum source / pump
- •Faulty PCM input
P0556 on Cadillac by Model
Cadillac Escalade(1 issue)
- Escalade Power Brake Assist Can Fade With Vacuum Pump Output (Recall 19V645000)2015-2017
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.
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View P0556 across all makes →Frequently Asked Questions
What does P0556 mean on 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 specifically, this code is documented across 1 model.
What causes P0556 on Cadillac vehicles?▼
Common causes on Cadillac: Faulty brake booster pressure sensor, Vacuum leak at the booster or hose, Wiring resistance / poor connection, Failing vacuum source / pump, Faulty PCM input. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0556 on a Cadillac?▼
Repair costs vary widely depending on the root cause and specific Cadillac model.
Which Cadillac models have P0556 documented?▼
Au7o has documented P0556 on 1 Cadillac model: Escalade.