AU
B2A2C92

This DTC indicates the front passenger side temperature flap actuator (air mix flap motor) cannot reach the target position or the position feedback signal is abnormal — Atto 3

Thermal Management System

This DTC indicates the front passenger side temperature flap actuator (air mix flap motor) cannot reach the target position or the position feedback signal is abnormal.

The integrated Body Control Module (BCM) drives this stepper/DC motor via the LIN bus or PWM signal to adjust the air mix flap opening and control the front passenger outlet temperature. "Cannot reach position" means the motor fails to reach the target angle within the set time (typically 3-5 seconds), or the position sensor feedback voltage deviates from the expected value by more than the threshold (generally >5%).

This fault disables front passenger temperature adjustment (no hot or cold air).

Severe cases may cause abnormal flap noise or trigger air conditioning system protection mode, but typically do not affect vehicle driving safety.

3
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Internal damage to the temperature damper actuator motor (worn gear set, seized motor rotor, or excessively worn carbon brushes), resulting in insufficient driving force to overcome damper resistance.
  • 2Poor wiring contact or open circuit, specifically spread or deformed terminal pins at the A/C fuse holder (e.g., IF03) in the instrument panel power distribution box, causing excessive power supply voltage drop (common after tapping power for aftermarket GPS, dash cams, or other accessories).
  • 3Air flap mechanism jammed (broken flap shaft, deformed plastic flap, detached foam seal causing binding, or foreign object blocking the air duct), stalling the motor and triggering protection.
  • 4Integrated Body Control Module (BCM) internal driver chip fault or LIN bus communication error, causing motor drive signal loss or position sampling circuit fault.
  • 5Temperature blend door position sensor (potentiometer) signal drift or open circuit; abnormal feedback voltage causes the BCM to incorrectly determine the door is not in position.
What To Do
  • 1
    Connect the VDS diagnostic tool, read all fault codes, and record the freeze frame data. Check if B2A2C92 occurs with related fault codes such as B2A2C14 (short to ground/open circuit). Check if the BCM software version requires an upgrade.
  • 2
    Check the air conditioning system fuse (IF03, etc.) in the instrument panel power distribution box. Inspect the fuse holder terminals for excessive clearance, looseness, or burn damage caused by tapping power for aftermarket equipment (GPS, dash cams). Measure the voltage drop across the fuse; it must be <0.1V.
  • 3
    Remove the front passenger glovebox or lower dashboard trim panel. Visually inspect the air mix door actuator (usually located on the right side of the HVAC assembly) for physical damage. Check the connector for oxidation or backed-out terminals. Measure the motor power supply (constant 12V), ground (<0.5Ω), and continuity of the LIN wire/PWM signal wire.
  • 4
    Disconnect the motor connector. Use an oscilloscope or multimeter to measure the BCM control signal output. If the signal is normal, connect an external 12V power supply directly to test if the motor operates through its full travel. Listen for abnormal gear slipping noise. Measure the position sensor feedback voltage; it should change linearly with rotation (0.5-4.5V).
  • 5
    Remove the actuator and manually turn the air flap shaft to check the internal HVAC mechanism for binding or excessive play. Check if the air flap seal has detached and is obstructing movement. If necessary, use an endoscope to inspect the inside of the air duct for foreign objects.
  • 6
    If testing confirms a faulty actuator, replace it with a genuine temperature blend door actuator (align the actuator to the zero position during installation; some models require blend door position learning/calibration using a diagnostic tool). Clear the fault code and test the adjustment function in all positions from full cold to full hot.
Real-World Cases
BYD DTC AI Analysis

Excessive clearance in fuse holder pins caused multiple motors to fail

✓
A 2018 Qin PRO DM owner reported the AC temperature and mode could not be adjusted. VDS scanning revealed motor DTCs B2A2C92 (passenger side temperature control motor position not reachable) and B2A2A92 (mode motor position not reachable). Inspection found a GPS retrofit tapping power from the air conditioning fuse. The GPS fuse blade was wider than OEM spec, spreading the IF03 fuse holder terminals and increasing contact resistance. Although the fuse appeared intact, insufficient voltage caused multiple air door actuators to fault simultaneously. Repaired the fuse holder terminals, restored the factory fuse, removed the added wiring harness, and cleared the fault.
Original source ↗
BYD DTC AI Analysis

Temperature blend door actuator internal gears slipping

✓
A 2019 Song MAX had constant cold air from the passenger side AC; the temperature could not be adjusted. The scan tool retrieved DTC B2A2C92. Live data showed target position at 100% (full heat) while actual position remained at 0% (full cold). Measured the actuator power supply, ground, and signal lines — all normal. Applied external power: the motor ran but the damper shaft did not turn, indicating worn plastic gears slipping inside the actuator. Replaced the passenger side temperature damper actuator. The actuator now follows temperature adjustment commands normally, the DTC cleared, and temperature adjustment function restored.
Original source ↗
BYD DTC AI Analysis

HVAC damper shaft binding, causing motor stall

✓
A 2017 Qin EV300 developed a clicking noise after the AC turned on, followed by passenger-side temperature control failure and DTC B2A2C92. Technicians removed the HVAC assembly and found the blend door shaft seized at the bushings from dust accumulation—the blend door had remained stationary for an extended period because the vehicle was always driven in recirculation mode with the temperature set to low. The actuator motor tried to drive the shaft but stalled against the resistance, eventually overheating and storing the fault. They cleaned the shaft bushings, applied specialized silicone-based grease, manually verified smooth operation, and reinstalled the original actuator (motor undamaged). Fault resolved. Advise the owner to regularly switch between temperature modes to prevent blend door mechanism seizure.
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: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.