Code Definition

P0555 — Brake Booster Pressure Sensor Signal Error

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0555

P0555 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0555 is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0555 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0555 fault code is set when the Engine Control Module (ECM) detects an error in the signal from the brake booster pressure sensor. This sensor measures the vacuum pressure within the brake booster, which is a critical component of the power brake system in vehicles. The brake booster assists in reducing the amount of physical effort needed to apply the brakes. An accurate signal from the brake booster pressure sensor is essential for the ECM to monitor and ensure proper functioning of the brake system. An error in this sensor's signal could be due to a malfunctioning sensor, wiring or con...

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