Brake Booster Pressure Sensor Circuit High
The P0558 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the brake booster pressure sensor that is higher than the expected range. This sensor monitors the vacuum or pressure in the brake booster to assist in braking and engine load calculations. A high voltage reading typically points to a short circuit to power, a faulty sensor, or wiring issues. This can affect brake assist and engine performance.
01. Most Common Causes
- Faulty brake booster pressure sensor
- Short circuit to voltage in sensor wiring
- Damaged connector or corroded terminals
- ECM internal fault (rare)
02. Symptoms You Will Notice
- Illuminated Check Engine Light
- Hard brake pedal or reduced brake assist
- Poor engine idle or stalling
- Increased stopping distance
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check freeze frame data.
Step 2: Inspect the brake booster pressure sensor connector and wiring for damage, corrosion, or shorts.
Step 3: Measure the sensor signal voltage with a multimeter; compare to manufacturer specs (typically 0.5-4.5V).
Step 4: If voltage is high (e.g., 5V), disconnect the sensor; if voltage drops, replace the sensor. If not, repair the short in wiring.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The code indicates a potential loss of brake assist, which can lead to a hard brake pedal and increased stopping distance, posing a safety risk.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and sensor replacement, depending on labor rates and parts pricing.