AU
C057F00

This DTC indicates the IPB (Integrated Power Brake) ECU detects abnormal power supply voltage to the brake booster motor — Atto 3

Braking System

This DTC indicates the IPB (Integrated Power Brake) ECU detects abnormal power supply voltage to the brake booster motor.

Conditions include voltage outside the normal range (9-16V), excessive voltage fluctuation, or power supply interruption.

The IPB system uses a motor-driven hydraulic pump to replace the conventional vacuum booster.

The ECU sets this fault when it detects an open circuit, short circuit, undervoltage (typically <9V), or overvoltage (>16V) in the motor power supply circuit.

This fault reduces or disables the brake assist function.

The system may enter Limp Home mode, resulting in a hard brake pedal, increased pedal travel, and an illuminated ABS/ESC warning lamp, severely compromising driving safety.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Fault in the IPB electro-hydraulic control module internal power management circuit or motor drive chip, causing abnormal voltage monitoring.
  • 2Severely discharged or aged 12V battery, or generator charging system fault, causing system voltage to drop below 9V.
  • 3Poor contact in IPB power supply circuit, blown fuse (e.g., F1/23 40A), loose relay connection, or damaged power wiring harness.
  • 4Water ingress, pin corrosion, pin back-out, or seal failure at the IPB wiring harness connector (usually located near the left longitudinal rail in the front compartment) causing a voltage drop.
  • 5Outdated IPB control unit software or abnormal calibration data causes voltage monitoring threshold drift.
What To Do
  • 1
    Use the VDS2000/VDS3000 diagnostic tool to read the complete fault codes and freeze frame data. Record key parameters at the time of the fault, such as vehicle speed, system voltage, and motor current, and confirm whether the fault is intermittent.
  • 2
    Check the 12V battery status: static voltage should be ≥12.4V, and starting voltage should be ≥9.6V. Verify the DC-DC converter output voltage is between 13.5-14.5V to rule out a power supply system fault.
  • 3
    Check the IPB-related fuses (typically 40A high-current fuses) and relays in the front compartment fuse box. Measure the voltage drop across the fuses; it must be <0.1V. Inspect the relay contacts for burning or pitting.
  • 4
    Disconnect the IPB wiring harness connector (e.g., B05). Inspect the pins for recession, corrosion, or water ingress. Measure the voltage between the power supply terminal (constant power +B) and ground; the voltage should be approximately 12V. Measure the resistance between the ground terminal (GND) and ground; the resistance should be < 1Ω.
  • 5
    Check the IPB ground wire connection point (usually ground point G105) for looseness or oxidation. Clean and tighten the ground bolt. Add a ground wire if necessary.
  • 6
    Use an oscilloscope to monitor the IPB motor supply voltage waveform. Check for voltage drops or spikes, and inspect the wiring for loose connections.
  • 7
    Flash the IPB control unit software to the latest version (such as an IPB software patch released after 2023), then complete system bleeding and longitudinal acceleration sensor calibration.
  • 8
    If all above checks are normal, replace the IPB electro-hydraulic control module assembly. Complete online coding, brake line bleeding, and ESC system calibration. Road test the vehicle to confirm the fault is resolved.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i auxiliary battery aging caused IPB voltage fault

✓
Vehicle parked 3 days. On startup, dashboard displayed "Brake System Fault". Retrieved fault code C057F00. Found 12V battery resting voltage at only 11.2V, dropping to 8.5V on cranking. Replaced battery; fault code cleared but returned after one week. Further inspection found alternator output at only 12.8V (low). Replaced alternator regulator; system voltage restored to 13.8V, fault permanently resolved. Analysis: Battery aging increased internal resistance; voltage drop during cold starting triggered IPB low-voltage protection.
BYD DTC AI Analysis

Water ingress corroded the IPB connector, causing intermittent voltage fault.

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After driving through water, the brake pedal became stiff with DTC C057F00 appearing intermittently. Inspection revealed water inside the IPB wiring harness connector (located beneath the left front side member). The power supply terminal (Pin 1) showed green corrosion with contact resistance of 3.2 Ω (normal <0.5 Ω). Cleared the water from the connector, cleaned the pins with precision electrical contact cleaner, applied conductive grease and replaced the seal. Resolved. Inspect IPB mounting location sealing on vehicles that have waded through water.
BYD DTC AI Analysis

IPB internal motor drive module damaged

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While driving, the ABS/ESC warning light suddenly came on, the brake pedal stiffened, and DTC C057F00 set current and would not clear. IPB supply voltage measured 12.8V (normal) with good ground, but the scan tool showed 0V for the IPB internal motor supply voltage. Disassembled the IPB module and found the internal motor drive MOSFET shorted, preventing the ECU from detecting motor supply voltage. Replaced the IPB electro-hydraulic control module assembly, performed coding and sensor calibration, and the fault resolved.
BYD DTC AI Analysis

Poor contact in the fuse holder caused voltage drop.

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After driving on rough roads, the brake system warning light came on intermittently. DTC C057F00 stored as history code. Inspection found the IPB fuse (40A) socket loose in the front compartment fuse box. Gap between fuse and terminal measured 1.8V voltage drop (normal <0.1V). Adjusted fuse holder tension, tightened terminal tabs using a special tool, applied conductive grease, and reinstalled. Road-tested 20 km with no fault recurrence. Analysis: Vibration caused poor fuse contact; voltage drop under high current triggered the fault.
BYD DTC AI Analysis

Software calibration fault causing false voltage fault

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During new-vehicle PDI, found DTC C057F00. Measured IPB supply voltage at 12.6V — normal. No wiring faults. TSB indicated an IPB software bug in this batch causes false voltage faults under specific conditions (e.g., rapid ignition switch cycling). Updated IPB control unit software via VDS (V1.2 to V1.4), completed longitudinal accelerometer calibration and ESC initialization. Fault code cleared and has not reappeared.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.
Data confidence: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.