AU
C057A00

DTC C057A00 indicates an abnormally high voltage or a short to power (B+) in the IPB (Intelligent Power Brake) internal brake booster temperature sensor power supply circuit — Seal 6 EV

Braking System

DTC C057A00 indicates an abnormally high voltage or a short to power (B+) in the IPB (Intelligent Power Brake) internal brake booster temperature sensor power supply circuit.

Integrated within the electronic brake booster, this sensor monitors the operating temperature of the booster motor or electronic control unit in real time to prevent brake performance degradation or motor burnout from overheating.

The IPB-ECU logs a power supply short circuit fault when the sensor supply line (typically a 5V reference voltage) continuously exceeds the calibrated threshold (generally above 6.0V or reaching the 12V battery voltage).

This fault triggers the IPB system safety protection mechanism.

It may limit or completely disable brake assist, degrade ABS/ESP functions, and force the vehicle into Limp Home Mode.

The system retains only basic unassisted hydraulic braking.

This constitutes a severe fault affecting driving safety.

The C057A00 fault code on the Seal 6 EV indicates high voltage or a short to power in the IPB brake booster temperature sensor supply circuit. This is a high-severity brake system fault that may reduce or disable brake assist and affect ABS/ESP operation. Common causes include damaged wiring shorting to 12V power or an internal sensor short. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Damaged sensor wiring harness insulation causing a short circuit to 12V constant power (B+) or the ignition power wire.
  • 2Breakdown or internal short circuit of the brake booster internal temperature sensor element, causing abnormal continuity between the power supply pin and the ground pin or signal pin.
  • 3Fault in the IPB electro-hydraulic module internal 5V reference voltage regulation circuit, causing abnormally high output voltage.
  • 4Water ingress, corrosion, or metallic debris in the sensor connector (usually located on the IPB assembly) causing abnormal continuity between terminals.
  • 5Crushed wiring or damaged insulation during accident repairs or vehicle modifications causes a misconnection or short circuit between the power wire and sensor signal wire.
What To Do
  • 1
    Safety preparation: Disconnect the high-voltage system service switch (for DM-i/EV models), disconnect the 12V battery negative terminal, and wait more than 3 minutes to completely power down the IPB system and release residual pressure.
  • 2
    Fault confirmation: Connect the VDS or a dedicated diagnostic tool to read fault codes. Confirm C057A00 is a current fault (Present) and will not clear. Record freeze frame data. Check for accompanying C057B00 (signal short circuit) or IPB communication fault codes.
  • 3
    Visual wiring inspection: Check the wiring harness path from the brake booster to the IPB module for abrasion, damaged insulation, and burn marks. Focus on harness fixing points and protective sleeves where the harness passes through the firewall, near the steering column, and in high-temperature areas of the front compartment.
  • 4
    Voltage measurement: Reconnect the battery, turn the ignition switch to ON, and measure the voltage between the temperature sensor connector power supply pin and ground. Normal voltage is 4.8-5.2V. If the reading is 12V or abnormally high, disconnect the connector and measure the voltage on the wiring harness side. If the voltage remains high, the wiring harness has a short circuit. If the voltage returns to normal, the sensor has an internal short circuit.
  • 5
    Harness continuity and insulation test: Disconnect the IPB module connector. Measure continuity between the sensor power supply harness and power supply (B+) (should have no continuity). Measure insulation resistance to ground (should be greater than 10 MΩ). Check the harness-to-body ground point for poor contact.
  • 6
    Sensor check: Measure the temperature sensor resistance (at room temperature, NTC types are typically 2-10kΩ, decreasing as temperature rises). If the resistance is abnormally low (close to 0Ω) or infinite, and there is no wiring harness fault, replace the brake booster assembly (the sensor is not available separately).
  • 7
    IPB module inspection: If the wiring harness and sensor test normal but the module output voltage remains abnormal (>5.5V), the internal IPB voltage regulator is faulty. Replace the IPB electro-hydraulic brake module assembly.
  • 8
    Repair verification: After repairing the short circuit or replacing the faulty component, clear the fault code. Perform the IPB system self-check, brake line bleeding, and pedal position learning procedures. Conduct a road test to confirm the fault does not recur and the brake assist function operates normally.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i firewall wiring harness chafing caused short to power

✓
At 32,000 km, the ABS and ESP warning lights suddenly illuminated on the dashboard along with a brake system malfunction warning. The diagnostic scanner read current DTC C057A00. Inspection found the wiring harness retention clip at the firewall had come loose. Long-term friction between the harness and steering column dust boot chafed through the insulation, shorting the temperature sensor supply wire (5V) to the air conditioning compressor clutch power wire (12V). Repaired the damaged wiring, rerouted and secured the harness to eliminate interference, and resolved the fault.
Original source ↗
BYD DTC AI Analysis

BYD Seal IPB temperature sensor seal failure, internal short circuit

✓
After driving through water approximately 30 cm deep, the brake pedal became stiff. The scanner displayed DTC C057A00. Disassembled the IPB assembly and found the seal between the brake booster housing and the wiring harness connector had deteriorated. Water ingress damaged the internal temperature sensor element, shorting the power supply to ground. As the sensor is integrated within the electronic vacuum booster, replacing it separately would not guarantee sealing integrity. Replaced the entire electronic brake booster assembly, then performed IPB online coding and brake bleeding. Fault cleared.
Original source ↗
BYD DTC AI Analysis

BYD Dolphin IPB sensor connector water ingress and corrosion

✓
Continuous use during the rainy season triggered the ESC warning light and DTC C057A00. Inspection found significant green corrosion on the temperature sensor connector at the IPB module (located on the side of the module). Moisture between the terminals conducted electricity and caused abnormal power supply. Cleaned the connector terminals with electronic contact cleaner, dried them, applied specialized conductive paste and silicone grease for waterproofing, and wrapped the connector with waterproof tape for extra protection. Cleared the fault codes after repair and monitored for one week without recurrence.
BYD DTC AI Analysis

Han DM-i IPB module internal reference voltage abnormal

✓
The vehicle had no collision or water damage history. The brake assist failure warning appeared suddenly during normal operation. Multimeter measurement showed the temperature sensor supply voltage at 8.7V (normal: 5V). With the sensor disconnected, the IPB module output still measured 8.7V, confirming an internal 5V regulator circuit fault in the IPB. Replaced the IPB intelligent integrated brake module assembly and performed ECU online coding, longitudinal acceleration sensor calibration and brake bleeding using a dedicated diagnostic tool. The brake system returned to normal.
BYD DTC AI Analysis

BYD Song Pro DM-i wiring error after accident repair

✓
After front-end collision repairs at an external workshop, the instrument cluster displayed multiple brake system fault codes, including C057A00 and U-class communication faults. Inspection found technicians had misconnected the temperature sensor power wire to the CAN-H harness while restoring the front compartment wiring, causing network interference and voltage abnormalities. Corrected the harness connections per the factory wiring diagram and initialized the IPB system to clear the faults.
Other Seal 6 EV 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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Seal 6 EV →Seal 6 EV overview →
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.