Brake Booster Pressure Sensor Circuit High
The P0558 code means the vehicle's onboard diagnostic system has detected: Brake Booster Pressure Sensor Circuit High. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
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What Are the Symptoms of P0558?
- Check Engine Light on
- False high pressure reading
- Start/stop system disabled
- No idle speed compensation for brake booster
What Causes P0558? (Most Likely First)
- Open circuit in brake booster sensor wiring Very High
- Failed sensor reading high (open internally) High
- Disconnected sensor connector Moderate
- Corroded pins causing high resistance Moderate
Can I Still Drive with P0558?
Short distances only. P0558 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does circuit high mean for P0558?
Circuit high means the sensor signal voltage is above the expected maximum. This usually indicates an open circuit in the sensor or wiring, causing the reference voltage to read through. The ECM sees this as no vacuum in the brake booster.
Is P0558 a brake safety concern?
P0558 does not directly affect brake booster operation. The brakes still work normally with vacuum assist. However, the ECM cannot monitor booster vacuum level, which may be important for safety features like the start/stop system.
Can a disconnected wire cause P0558?
Yes. A disconnected sensor connector is one of the most common causes of P0558. Check the sensor connector first before replacing the sensor itself. The connector may have vibrated loose or corroded.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0558?
-
Read sensor value; an abnormally high voltage regardless of engine vacuum confirms circuit high
-
Check sensor connector for disconnection or corrosion
-
Measure sensor output voltage; a reading stuck near reference voltage indicates an open circuit
-
Test sensor with a hand vacuum pump to verify it responds to vacuum changes
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0558?
- 2010-2020 Chevrolet Equinox
- 2012-2019 Kia Optima
- 2008-2018 Hyundai Sonata
- 2011-2020 Mazda CX-5
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