Brake Booster Pressure Sensor Circuit Range/Performance

Where it lives

For P0556, the part to look at first is the sensor named here.

Check these first

• A contaminated brake booster pressure sensor
• A sensor that drifted out of calibration
• A weak ground shifting the sensor signal
• A leaking brake booster changing the readings
• An incorrect sensor fitted to the vehicle

What to do next

1. Inspect the sensor connector for corrosion or water
2. Compare the sensor reading with a known pressure
3. Check the sensor ground circuit
4. Test the brake booster for internal leaks
5. Replace the sensor if it is out of range
6. Clear the code and retest

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