UAE
AU
B2A0717

This DTC indicates the A/C controller or thermal management system control module detects a power supply voltage exceeding the 16V safety threshold — Atto 3

Thermal Management System

This DTC indicates the A/C controller or thermal management system control module detects a power supply voltage exceeding the 16V safety threshold.

In BYD new energy vehicles, the DC-DC converter typically converts high-voltage traction battery energy to power the low-voltage system (12V/14V system).

Normal output voltage should range between 13.5V and 14.5V.

When the monitoring point voltage continuously exceeds 16V, the controller identifies an overvoltage condition and triggers a protection mechanism to prevent electronic component damage.

This fault may restrict A/C system functions, reduce thermal management efficiency, or force the system into a power derating mode.

Extreme cases may damage sensitive electronic components on the control board.

The '161' in the DTC typically refers to a specific voltage monitoring circuit or sensor number.

3
Cases Logged
Real-World Cases
BYD DTC AI Analysis

B2A0717 Overvoltage Fault: Basic Definition and Troubleshooting

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AC system or related control module logged voltage overvoltage fault, potentially restricting AC function, causing control panel anomalies, or triggering protective shutdown. VDS scan retrieved DTC B2A0717 (161 Voltage Overvoltage), localized to the power supply circuit. Measured supply voltage to relevant sensors and control module exceeded system calibration threshold (e.g., above 16V). Fix involved checking generator output, voltage regulation module and wiring; replacing the faulty voltage regulator or repairing shorts/poor connections causing the voltage anomaly.
Original source ↗
BYD DTC AI Analysis

BYD Air Conditioning Controller Abnormal Voltage Fault

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With the A/C on, the control panel intermittently goes black or displays "Please check air conditioning system". Cooling is intermittent and the system fault light comes on. VDS scanning revealed A/C controller fault codes (similar to B2A series power faults). Voltage measurements at the controller supply pins showed excessive fluctuation or sustained overvoltage, setting DTC B2A0717. Inspection of the power circuit found a failed voltage regulator module. Replaced the A/C controller power supply voltage regulator module, repaired the harness contact issues, and cleared the codes. System returned to normal.
Original source ↗
BYD DTC AI Analysis

BYD New Energy Vehicle High Voltage Interlock Loop Voltage Fault

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Dashboard shows "EV Function Limited" or "Check Powertrain". Vehicle cannot enter EV mode and intermittently fails to ready up. VDS scan reveals voltage-related DTCs in the BMS or HVAC thermal management system (refer to B2A series). Check the power wiring between the high voltage distribution box and AC controller; overvoltage present. Voltage at sensor No. 161 or the control point measures outside the normal range. Check DC-DC converter output voltage. Replace the damaged fuse or relay in the high voltage distribution box. Repair the AC controller power supply wiring. Fault resolved.
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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: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.