P0558 indicates that the brake booster pressure sensor is reporting a voltage higher than the expected range, suggesting excessive pressure or a fault in the sensor circuit. The code is triggered when the PCM detects a signal that exceeds normal operating limits.
The sensor inside the brake booster can develop an internal short or drift, causing it to output a high voltage signal.
Damaged wiring, corrosion, or a loose connector at the sensor can create a high-resistance condition that the PCM interprets as high voltage.
A leak can reduce vacuum pressure, causing the sensor to register abnormally high pressure readings.
A rare fault in the PCM's input circuitry can misinterpret sensor signals, but this is less common than sensor or wiring problems.
No, the PCM is rarely the cause; most often the sensor, wiring, or a vacuum leak is responsible.
Yes, a significant vacuum leak in the brake booster can cause the sensor to read high pressure and set P0558.
After the underlying issue is repaired, the code will clear after a few drive cycles or can be cleared with a scan tool.
Yes, the sensor is more likely to fail than the PCM, especially in older vehicles or those exposed to moisture.