AU
U030000

In the BYD IPB (Intelligent Power Brake) integrated braking system, U030000 indicates the brake control unit (IPB ECU) internal software is incompatible with the vehicle network configuration — Atto 8

Braking System

In the BYD IPB (Intelligent Power Brake) integrated braking system, U030000 indicates the brake control unit (IPB ECU) internal software is incompatible with the vehicle network configuration.

Specifically, the IPB module software version number, Calibration Verification Number (CVN), or configuration word (Coding) does not match the vehicle VCU, Gateway, and other CAN nodes.

This prevents the brake control strategy from loading normally or causes verification failure.

The fault triggers the system safety protection mechanism, restricting regenerative braking, Automatic Emergency Braking (AEB), and ESC functions.

Severe cases cause a hard brake pedal, limit brake assist, or force the vehicle into limp mode.

This functional fault compromises driving safety.

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Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Incorrect IPB ECU software version (mistakenly flashed software package for another vehicle model, model year, or trim level)
  • 2Failure to perform online matching, coding, and anti-theft synchronization after replacing the IPB assembly with a salvaged or used unit.
  • 3Interrupted software flashing (battery voltage below 12V, unstable OBD connection, or diagnostic tool crash) corrupted the program block.
  • 4Vehicle network configuration data (CVN/AS-BUILT data) missing or inconsistent with gateway module configuration.
  • 5Corrupted IPB internal EEPROM data (due to prolonged battery discharge, strong electromagnetic interference, or hardware aging).
What To Do
  • 1
    Use VDS2000 or a BYD dedicated diagnostic tool to read the fault code. Confirm U030000 is a current fault, not a history fault. Record the current IPB software version number (e.g., BGM+ version number) and hardware part number.
  • 2
    Check the IPB ECU power supply (constant power 30+B, ignition switch IG power), ground points (G101/G102), and CAN-H/CAN-L voltages (recessive 2.5V, dominant 3.5V/1.5V) to rule out power supply fluctuations as the cause of software checksum errors.
  • 3
    Verify the vehicle VIN and IPB label part number to confirm the hardware matches the vehicle configuration (e.g., Song PLUS DM-i requires a specific IPB model; do not mix fuel and hybrid version IPBs).
  • 4
    Perform 'Online Programming' or 'Software Refresh': Connect the diagnostic tool to the BYD cloud server and download the latest IPB software package for the corresponding VIN (usually .hex or .s19 format). During flashing, maintain battery voltage above 12V and do not operate high-power electrical equipment such as doors or air conditioning.
  • 5
    After completing the refresh, perform the 'System Configuration' (enter the correct Coding code), 'Sensor Zero Point Calibration' (longitudinal acceleration sensor and pressure sensor calibration), and 'Brake Line Bleeding' procedures.
  • 6
    If the software flash fails, the fault code does not clear, or the code returns, install a new IPB assembly. Complete online matching and coding, then fill and bleed the brake fluid.
Real-World Cases
BYD DTC AI Analysis

Replaced IPB assembly with used unit; DTC U030000 now present.

✓
A 2021 Song PLUS DM-i had its IPB assembly replaced with a salvage unit after an accident. After installation, the ABS and ESC warning lights came on in the instrument panel with DTC U030000. Diagnosis revealed the salvage part came from a gasoline Song Pro with incompatible software. Technicians used VDS2000 to run the 'Replace ECU' procedure, performing online programming and writing the Song PLUS DM-i Coding. Pressure sensor calibration cleared the fault.
BYD DTC AI Analysis

Interrupted software update locked up the module

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During IPB software upgrade, loose USB connection on diagnostic tool interrupted programming. DTC U030000 could not be cleared afterwards, and IPB could not enter programming mode. Forced flash in Boot mode after power-down/sleep failed. Replaced IPB assembly. Use regulated power supply (14V/50A) before flashing. Do not rely solely on vehicle battery.
BYD DTC AI Analysis

Software verification failed after 12V battery discharge

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Vehicle sat for one month; battery voltage dropped to 8.5V. After jump-starting, the instrument cluster displayed 'Braking system fault' and the scan tool retrieved DTC U030000. Prolonged low voltage caused an EEPROM data checksum failure in the IPB. Performed a 'software reset' with the scan tool and reflashed the same software version. Fault code cleared and functions returned to normal without hardware replacement.
BYD DTC AI Analysis

CVN data lost after accident repair

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Replaced the gateway module and IPB following front-end collision repairs. Post-repair, DTC U030000 set and AEB failed. The new gateway module's CVN (configuration data) did not match the original vehicle, preventing the IPB from recognising the network configuration. Downloaded the original vehicle backup data via the BYD DMS system and reprogrammed both the gateway and IPB. Synchronised the network configuration to clear the fault.
Other Atto 8 Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.