P0556 Mini Brake Booster Pressure Sensor Circuit Range/Performance

Possible causes

– Faulty Brake Booster Pressure Sensor
– Brake Booster Pressure Sensor harness is open or shorted
– Brake Booster Pressure Sensor circuit poor electrical connection

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0556 Mini Description

Brake booster pressure sensor is connected to brake booster by a hose. It detects brake booster pressure and sends the voltage signal to the Engine Control Module (ECM). The sensor uses a silicon diaphragm which is sensitive to the change in pressure. As the pressure increases, the voltage rises.