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DTC code page

P0558: Brake Booster Pressure Sensor Circuit High

Quick answer: The PCM sees the brake booster pressure sensor signal stuck higher than it should be.

Drivers also search this fault as brake booster pressure sensor circuit high, brake booster pressure high input, P0558 code.

Severity: high Family: powertrain Related paths: 13
Meaning

What P0558 usually means

P0558 matters because it lives in the awkward overlap between engine vacuum, brake assist, and drivability complaints. The code means the brake booster pressure sensor circuit is reporting a high signal or otherwise looks electrically too high to trust. That can happen because the sensor is biased, the vacuum supply really is abnormal, the harness is shorted to voltage, or the booster side is not seeing the pressure change the PCM expects. Drivers often notice some mix of hard brake pedal, rough idle, hissing vacuum leak behavior, or a reduced-power-style warning depending on the platform. That makes P0558 more than a pure brake code. It often belongs in vacuum-leak diagnosis too.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Ask whether the brake pedal feels harder than normal. That symptom matters more than the code title alone.
  • Inspect the booster vacuum hose and check valve because a real vacuum fault can overlap with sensor data faults.
  • Listen for hissing and watch idle quality. Many P0558 cases live partly in the vacuum-leak world.
Driving risk

Can you keep driving?

Treat P0558 seriously if the brake pedal is hard or brake assist feels weak. The vehicle may still stop, but emergency braking effort can increase. Diagnose it soon and avoid pushing the car until the vacuum story is clear.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Symptoms

Common symptoms

Likely causes

Common causes behind this code

  • Brake booster pressure sensor biased high or failed internally
  • Signal circuit shorted to voltage or suffering from connector damage
  • Vacuum hose, check valve, or booster leak changing the expected pressure pattern
  • Engine vacuum problem affecting booster pressure during idle and braking
  • Wiring harness damage near the booster or intake manifold area

Cause phrases often tied to this code: bad brake booster pressure sensor, vacuum leak, short to voltage, booster hose leak, check valve issue.

Diagnostic order

Suggested workflow

  1. Inspect the booster vacuum hose, check valve, and sensor connector for obvious leaks or damage.
  2. Compare sensor reading with actual vacuum conditions if scan data and a gauge are available.
  3. Check signal voltage, reference, and ground integrity at the pressure sensor.
  4. Verify whether the brake pedal feel changes during the same conditions that set the code.
  5. Repair the proven sensor, wiring, or vacuum-supply fault and confirm both drivability and brake assist improve.
Avoid guesswork

Common mistakes

  • Replacing the sensor without checking the booster hose and one-way check valve.
  • Treating P0558 like a brake-only code when the engine vacuum side is part of the system.
  • Ignoring driver complaints of hard pedal because the vehicle still stops.
Repair path

Practical fix guidance

  • Fix the confirmed sensor, circuit, booster vacuum hose, check valve, or engine-vacuum problem.
  • After repair, verify normal brake assist, stable idle, and no returning pressure-sensor fault.
  • If the engine still idles lean or rough, finish the vacuum-leak diagnosis rather than assuming the brake side solved everything.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0558

Useful when the driver knows the wording but not the exact DTC yet.

  • brake booster pressure sensor circuit high
  • brake booster pressure high input
  • P0558 code
Related search intent

Queries this page can answer naturally

  • P0558 code meaning
  • what does P0558 mean
  • hard brake pedal with P0558
  • brake booster pressure sensor high
FAQ

Quick questions about P0558

Can P0558 make the brake pedal hard?

Yes. If brake booster vacuum or sensor plausibility is part of the fault, reduced brake assist can be part of the complaint.

Is P0558 only a bad sensor?

No. Vacuum leaks, check-valve faults, and wiring issues are common too.

Why does P0558 sometimes come with rough idle?

Because the booster hose and sensor live in the engine-vacuum system, and a leak there can disturb idle quality.