BYD ATTO 3 (e-Platform 3.0) B2AB249 Air Conditioner Compressor IPM IGBT Fault

B2AB249 indicates a fault involving the intelligent power module (IPM) and insulated-gate bipolar transistor (IGBT) within the electric A/C compressor drive system. The fault affects the compressor’s high-voltage power electronics, which control the electric motor responsible for circulating refrigerant through the air-conditioning system. The BYD ATTO 3 uses BYD’s e-Platform 3.0 architecture, with this generation introduced from 2022 and continuing onward.

Symptoms

• Air conditioner does not produce cold air
• Electric compressor fails to start
• A/C cooling may be intermittent
• Compressor may shut down shortly after activation
• Climate control warning may be displayed
• Cabin temperature remains higher than requested
• Compressor or high-voltage HVAC fault codes may be stored
• A/C system may disable compressor operation as a protective measure

Possible Causes

• Internal IPM or IGBT failure
• Compressor inverter power-electronics fault
• Internal electric compressor failure
• High-voltage power supply problem
• Damaged compressor high-voltage wiring
• Loose or damaged compressor connector
• Poor electrical terminal contact
• Electrical overcurrent or overvoltage condition
• Thermal protection event
• Compressor motor fault affecting the inverter
• Low or unstable auxiliary electrical supply
• Internal compressor control fault

Diagnosis

Diagnosis should begin by confirming B2AB249 and checking for related compressor, high-voltage, motor, insulation, and communication faults. Compressor power supply, operating status, high-voltage circuit condition, control signals, fault history, and relevant compressor data should then be evaluated against manufacturer specifications.

The diagnostic direction should distinguish an external power, wiring, or control issue from an internal compressor IPM/IGBT failure before the compressor is condemned. Because the compressor contains high-voltage power electronics, manufacturer isolation procedures and appropriate EV safety equipment are essential during diagnosis. Accurate diagnosis is particularly important when parts availability and repair costs are considerations for New Zealand vehicle owners.

Accurately diagnosing this fault often requires manufacturer testing procedures, wiring diagrams, connector pinouts, specifications, and system calibration information. Access to the factory service manual significantly reduces diagnostic time and helps prevent unnecessary parts replacement.

Applicable Years

2022, 2023, 2024, 2025, 2026, onwards

To order the correct OEM Service and Repair Manual for your BYD ATTO 3, submit your request using the form below and our team will provide the ordering details.