AU
C057F00

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

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 — Qin Plus
  • 1Fault in the internal power management circuit or motor drive chip of the IPB electro-hydraulic control module, 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 the IPB power supply circuit, blown fuse (e.g., F1/23 40A), loose relay connection, or damaged power wiring harness.
  • 4Voltage drop caused by water ingress, pin corrosion, pin back-out, or seal failure at the IPB wiring harness connector (usually located near the left side member in the front compartment).
  • 5Outdated IPB control unit software version 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, to confirm if the fault is intermittent.
  • 2
    Check the 12V battery status: static voltage should be ≥12.4V and cranking voltage should be ≥9.6V. Verify the generator output voltage is between 13.5-14.5V to rule out a power supply system fault.
  • 3
    Check the IPB-related fuse (usually a 40A high-current fuse) and relay in the front compartment fuse box. Measure the voltage drop across the fuse; 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 backout, corrosion, or water ingress. Measure the voltage between the power supply terminal (constant +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 an additional ground wire if necessary.
  • 6
    Use an oscilloscope to monitor the IPB motor supply voltage waveform. Check for voltage drops or spike interference, and inspect the wiring for loose connections.
  • 7
    Update the IPB control unit software to the latest version (such as an IPB software patch released after 2023), then bleed the system and calibrate the longitudinal acceleration sensor.
  • 8
    If all the above checks are normal, replace the IPB electro-hydraulic control module assembly. Perform online coding, bleed the brake lines, and calibrate the ESC system, then road test the vehicle to confirm fault resolution.
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.

✓
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

✓
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 Qin Plus Fault Codes
B1108For 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.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
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.