The P0556 trouble code indicates that the brake booster pressure sensor circuit is experiencing a range or performance issue. The brake booster pressure sensor measures the vacuum pressure in the brake booster and sends this information to the engine control module (ECM) or powertrain control module (PCM). When the sensor circuit operates outside of its expected range or performance parameters, this trouble code is triggered.
Brake Booster Pressure Sensor Circuit Range/Performance
Code symptoms P0556.
1. Illumination of the Check Engine Light.
2. Possible reduction in brake assist performance.
3. Changes in brake pedal feel, such as increased stiffness or reduced responsiveness.
4. Vehicle may require more effort to stop.
This code is common in brands such as:: Chevrolet, Renault, Ford, Toyota, Nissan, Mercedes Benz, Honda.
Causes of the code P0556.
1. Faulty brake booster pressure sensor.
2. Damaged, corroded, or loose wiring or connectors in the sensor circuit.
3. Vacuum leak in the brake booster system.
4. Malfunctioning ECM or PCM.
Code Solutions P0556.
1. Inspect the brake booster pressure sensor and its wiring for any signs of damage, corrosion, or loose connections. Repair or replace any damaged components as necessary.
2. Test the brake booster system for vacuum leaks. Common areas to check include hoses, fittings, and the brake booster itself. Repair or replace any leaking components.
3. Clear the trouble code from the vehicle’s computer memory and perform a test drive to confirm that the issue has been resolved.
4. If the problem persists, further diagnosis may be needed. This may involve using a scan tool to monitor the sensor’s readings during brake pedal application to identify any abnormalities.
5. If the brake booster pressure sensor is found to be faulty, it should be replaced with a new one.