OBD-II code · Powertrain (generic)
P0557 Brake Booster Pressure Sensor Circuit Low
Same as P0555 with the signal voltage below the plausible range. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
Is it safe to drive with P0557?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.4–1.4 h
- Emissions test
- Usually unaffected
- Parts involved
- Brake Booster Pressure Sensor
Related codes
- P0554Power Steering Pressure Sensor Intermittent
- P0555Brake Booster Pressure Sensor Circuit
- P0556Brake Booster Pressure Sensor Circuit Range or Performance
- P0558Brake Booster Pressure Sensor Circuit High
- P0559Brake Booster Pressure Sensor Circuit Intermittent
- P055AEngine Oil Pressure Sensor or Switch B Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.