P0557

Symptoms

• Hard brake pedal (increased pressing force)
• Increased braking distance
• Check Engine Light and/or Brake Warning Light Illuminates
• Hissing sound when pressing the brake pedal
• Emergency engine operation

Causes

• Broken signal wire of the amplifier pressure sensor
• Sensor circuit short to ground
• Vacuum booster pressure sensor malfunction
• Vacuum leak in brake booster or lines
• Vacuum pump malfunction (on diesel engines)

How to Fix

1. IMMEDIATELY check braking performance and brake pedal stiffness.
2. Inspect the booster vacuum hoses for cracks and leaks.
3. Check the vacuum level in the amplifier (should be 650–750 mmHg)
4. Measure the voltage and resistance in the pressure sensor circuit
5. If the circuit malfunctions, restore the wiring or replace the sensor
6. If there is a vacuum leak, replace the amplifier membrane or the entire amplifier

Related codes

Error P0557 by Vehicle Brand