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B2A2B92

This fault code indicates the driver-side HVAC (Heating, Ventilation, and Air Conditioning) temperature blend door actuator (hot/cold blend door motor) cannot reach the target position or the position feedback signal is abnormal — Atto 3

Thermal Management System

This fault code indicates the driver-side HVAC (Heating, Ventilation, and Air Conditioning) temperature blend door actuator (hot/cold blend door motor) cannot reach the target position or the position feedback signal is abnormal.

The actuator uses a stepper motor or DC motor to drive a gear mechanism, adjusting the hot/cold blend door opening (0-100%).

This accurately controls the airflow mixing ratio through the heater core and evaporator, providing stepless adjustment of the outlet air temperature.

The air conditioning controller (AC ECU) logs this fault code if the deviation between the actual and target positions continuously exceeds the calibrated threshold (typically 5-10%) or if the motor stall current times out.

Triggering conditions include a faulty motor drive circuit, position sensor (potentiometer) signal drift, a binding gear drive mechanism, or excessive mechanical resistance at the blend door shaft.

This fault causes driver-side temperature adjustment failure, abnormal outlet air temperature (stuck excessively cold or hot), unstable temperature control in automatic air conditioning mode, or a clicking gear noise during temperature adjustment.

3
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Yuan PLUS dashboard rattle with DTC B2A2B92

✓
The owner scanned with a Launch golo pro4 and found DTC B2A2B92 (driver-side temperature control motor not reaching position) and B2A2B14 (driver-side temperature control motor short-to-ground or open circuit) in the body module–AC controller. The symptom was a faint, intermittent clicking noise from inside the dashboard, most noticeable when adjusting the temperature or starting the AC. Although the motor wasn't reaching position, cooling and heating still worked. Upon disassembly, the owner found slight wear on the actuator gear. Since the function hadn't completely failed and the part needed ordering, the owner decided to defer the repair and replace the actuator assembly when the fault worsened.
Original source ↗
BYD DTC AI Analysis

Qin EV Intermittent AC Cooling Failure Associated with DTC B2A2B92

✓
The owner reported the vehicle A/C frequently stopped cooling but returned to normal after driving for a period or restarting the vehicle. Scanning showed fault code B2A2B92 (HVAC blend door actuator position fault). Further inspection found the driver's side temperature blend door stuck at maximum heat (100%) when the fault occurred. Even with the temperature set to low, the mixed hot and cold air could not achieve cooling. This case shows B2A2B92 causes not only abnormal noise but can also stick the blend door in a fixed position, causing intermittent A/C failure. Inspect the blend door actuator mechanical linkage and internal gear condition.
Original source ↗
BYD DTC AI Analysis

Song MAX Blend Door Actuator Gear Wear Replacement Case

✓
A 2018 Song MAX owner reported the driver's side AC temperature would not adjust and remained stuck on warm. The technician scanned with VDS and found DTC B2A2B92. Data stream showed target position at 20% with actual position stuck at 95% (full heat). After removing the driver's side temperature blend door actuator, the technician found severe wear and broken teeth on both the drive and driven gears in the internal plastic gear set; the motor spun freely without moving the door. The technician replaced the blend door actuator (part number: HAD-8113210), ran the door initialization procedure, cleared the fault code, and restored normal temperature control. This case represents a typical mechanical failure mode for DTC B2A2B92.
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.