Brake Booster Pressure Sensor Circuit Malfunction
The P0555 code indicates a problem in the brake booster pressure sensor circuit. This sensor monitors vacuum or pressure in the brake booster to assist braking. A fault can cause the powertrain control module (PCM) to detect an abnormal voltage signal, leading to reduced brake assist and potential safety risks.
01. Most Common Causes
- Faulty brake booster pressure sensor
- Open or shorted wiring in the sensor circuit
- Poor electrical connection at the sensor connector
- Failed PCM (rare)
02. Symptoms You Will Notice
- Illuminated Check Engine Light
- Hard brake pedal (increased effort required)
- Reduced braking performance
- Possible ABS or traction control warning lights
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0555 and check for other codes.
Step 2: Visually inspect the brake booster pressure sensor and wiring for damage or corrosion.
Step 3: Test the sensor's voltage signal with a multimeter (typically 0.5-4.5V) and compare to specifications.
Step 4: Check for continuity and shorts in the circuit between the sensor and PCM.
Step 5: If all else is fine, replace the brake booster pressure sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. The code indicates a potential loss of brake assist, which can lead to longer stopping distances and increased risk of accident. Have the vehicle inspected immediately.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the vehicle and shop rates. The sensor itself is often inexpensive.