BMW DTC P0557 – Brake Booster Pressure Sensor Circuit Low
DTC P0557 meaning on BMW
DTC P0557 on a BMW indicates a fault with the brake booster pressure sensor circuit. The Power Brake Booster Pressure Sensor is responsible for monitoring the pressure within the brake booster. When the sensor detects a low voltage signal, triggering the P0557 trouble code, it suggests that there is an issue with the sensor circuit operating below the specified threshold.
BMW DTC P0557 symptoms
Symptoms of DTC P0557 on a BMW may include:
- Check Engine Light illuminated on the dashboard
- Brake system warning light may be on
- Decreased brake assist functionality
- Hard brake pedal feel
BMW DTC P0557 causes
Potential causes of DTC P0557 on a BMW include:
- Faulty brake booster pressure sensor
- Corroded or damaged wiring in the sensor circuit
- Issues with the brake booster itself
- Electronic control module (ECM) failure
BMW DTC P0557 seriousness
While DTC P0557 may not always result in immediate safety concerns, it is crucial to address this issue promptly. A malfunctioning brake booster pressure sensor can affect the performance of the brake system, potentially compromising vehicle safety. It is recommended to have the problem diagnosed and repaired as soon as possible.
How to diagnose DTC P0557 on BMW
To diagnose DTC P0557 on a BMW, a mechanic may perform the following steps:
- Use a diagnostic scanner to retrieve the trouble codes stored in the vehicle’s ECM
- Inspect the brake booster pressure sensor and its wiring for any visible damage or corrosion
- Test the sensor’s voltage output using a multimeter to determine if it is within specifications
- Check the brake booster for any signs of malfunction
How to fix DTC P0557 on BMW
To fix DTC P0557 on a BMW, the following steps may be taken:
- Replace the faulty brake booster pressure sensor if it is determined to be the cause of the issue
- Repair or replace any damaged wiring in the sensor circuit
- If the brake booster is faulty, it may need to be replaced
- Clear the trouble codes from the ECM after the repairs have been completed
How to erase DTC P0557 on BMW
To erase DTC P0557 on a BMW, follow these steps:
- Use a diagnostic scanner to access the vehicle’s ECM
- Select the option to clear the trouble codes stored in the system
- Confirm the action and wait for the scanner to erase the DTC P0557 code
- Once the code has been successfully cleared, verify that the Check Engine Light is no longer illuminated
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
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