Code Definition

P0558 — Brake Booster Pressure Sensor Signal High

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

About P0558

P0558 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 P0558 is stored, the module has detected a signal or supply voltage higher than the expected operating range; and 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 P0558 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

This fault code is set when the engine control module (ECM) or brake system control module detects a higher than normal voltage from the brake booster pressure sensor. The brake booster pressure sensor measures the vacuum or pressure level within the brake booster, playing a crucial role in the vehicle's braking efficiency and power brake assist functionality. A high signal from this sensor may indicate an issue within the sensor circuit, suggesting that the pressure in the brake booster is inaccurately being read as too high, which could affect braking performance.

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