P0558 - Brake Booster Pressure Sensor Circuit High
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0558 is a generic diagnostic trouble code (DTC) indicating that the Engine Control Module (ECM/PCM) has detected a voltage signal from the Brake Booster Pressure Sensor that is above the calibrated limit. This sensor monitors the vacuum level inside the brake booster to ensure adequate power braking assist. A 'high' condition typically signifies an open circuit or a short to voltage (5V reference). The ECM uses this input to manage supplemental vacuum sources, such as an electric vacuum pump, and to ensure safety during braking maneuvers.
Possible Causes
Faulty Brake Booster Pressure Sensor (internal short)
Short to voltage in the wiring harness (5V reference)
Open circuit (broken wire) or poor ground connection
Faulty Engine Control Module (PCM/ECM)
Symptoms
Recommended Solution
Workflow
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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