Brake Booster Pressure Sensor Circuit High
The P0558 code indicates that the brake booster pressure sensor circuit is reading a voltage higher than the expected range. This sensor monitors the vacuum or pressure in the brake booster to assist with braking. A high voltage signal can be caused by a faulty sensor, wiring issues, or a problem with the brake booster itself. This can lead to increased brake pedal effort and potential safety concerns.
1. Most Common Causes
- Faulty brake booster pressure sensor (internal short circuit)
- Signal circuit shorted to battery voltage (B+)
- 5V reference circuit shorted to voltage
- Sensor ground circuit open or high resistance
- Damaged, corroded, or loose connector terminals
- Severe vacuum leak in brake booster or hoses (causing high actual pressure reading)
- Internal PCM/ECM failure (rare)
2. Symptoms You Will Notice
- Hard brake pedal
- Increased stopping distance
- Brake warning light illuminated
- Reduced brake assist
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and check freeze frame data.
Step 2: Visually inspect the brake booster pressure sensor and wiring for damage or corrosion.
Step 3: Test sensor voltage with a multimeter; compare to manufacturer specifications.
Step 4: Check for shorts to voltage or ground in the sensor circuit.
Step 5: Replace the sensor if readings are out of range and wiring is intact.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended as it can cause increased brake pedal effort and longer stopping distances, posing a safety risk.
How much does it cost to fix?▼
Typically between $50 and $150 for parts and labor, depending on the sensor cost and labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.