AU
B2A2C14

DTC B2A2C14 indicates a drive circuit fault in the front passenger side temperature blend door actuator (hot/cold motor), specifically a short to ground (abnormal connection to vehicle ground causing overcurrent) or an open circuit (circuit interruption, infinite resistance) — Atto 3

Thermal Management System

DTC B2A2C14 indicates a drive circuit fault in the front passenger side temperature blend door actuator (hot/cold motor), specifically a short to ground (abnormal connection to vehicle ground causing overcurrent) or an open circuit (circuit interruption, infinite resistance).

The integrated Body Control Module (BCM) controls this motor via a PWM signal or stepper drive to adjust the front passenger side hot/cold air mixing ratio, enabling dual-zone climate control.

The BCM sets this DTC upon detecting abnormal motor drive current (excessive or zero), an abnormal position feedback signal, or a LIN communication fault.

This fault prevents front passenger side temperature adjustment (sticking in the cold or hot position).

In severe cases, the BCM may enter protection mode, limiting overall air conditioning system functionality and potentially affecting the thermal management system's control of battery or motor temperatures.

The B2A2C14 fault code on the Atto 3 indicates a high-severity fault with the front passenger temperature blend door actuator, which controls hot and cold air mixing. It may be caused by a shorted or open wiring harness, often from rubbing damage, or an internal actuator motor failure. The passenger temperature may stick hot or cold. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
3
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Harness wear causing short to ground: The harness retaining clip near the evaporator housing detaches, causing the harness to rub against the steering column or instrument panel frame. This damages the power or signal wire insulation, resulting in a short to ground.
  • 2Internal motor fault: Heating/cooling motor internal coil short circuit or burnout, open circuit due to worn carbon brushes, or gear mechanism binding or slipping causing abnormal drive current.
  • 3Abnormal power supply: Poor contact at dashboard fuse IF03 (especially when aftermarket dash cam/GPS power taps deform the fuse holder terminals or create excessive clearance), causing an intermittent connection or voltage drop.
  • 4Poor connector contact: Backed-out pins, oxidized or corroded pins, or loose terminals at the motor connector behind the glovebox cause an intermittent open circuit or high resistance.
  • 5Mechanical binding: A corroded temperature flap shaft, deformed linkage, or seized flap blade causes excessive motor load, triggering overcurrent protection and a false short-circuit detection.
What To Do
  • 1
    Connect the VDS or dedicated diagnostic tool, read all fault codes, and record the freeze frame data. Attempt to clear the fault codes, adjust the A/C temperature, and observe if the fault returns immediately.
  • 2
    Check fuse IF03 (air conditioning system fuse) in the instrument panel distribution box and verify the correct rating (usually 10A or 15A). Check if aftermarket equipment has spread or deformed the fuse holder terminals. Restore terminal clamping force if necessary.
  • 3
    Remove the front passenger glovebox to access the temperature damper actuator (hot/cold motor). Check the wiring harness connector for looseness or backed-out pins. Measure the motor supply voltage (should be 12V±0.5V) and ground wire continuity (resistance should be less than 1Ω).
  • 4
    Disconnect the motor connector and use a multimeter to measure the motor resistance (normal range is usually 30-100 Ω; refer to the repair manual for specific values). A reading of 0 Ω indicates an internal short circuit. An infinite reading indicates an internal open circuit.
  • 5
    Check the wiring harness routing, focusing on the section from the evaporator unit to the instrument panel crossmember. Inspect for interference or chafing against the steering column and instrument panel frame. Repair any damaged wiring and re-secure the harness retaining clips.
  • 6
    Manually move the temperature flap linkage and check the flap mechanism for binding, corrosion, or abnormal noise. If necessary, clean and lubricate the flap shaft or replace the evaporator housing assembly.
  • 7
    If the motor and wiring harness are normal, check the continuity of the drive circuit from the BCM to the motor. Replace the Integrated Body Control Module (BCM) if necessary.
  • 8
    After replacing the faulty component, use the diagnostic tool to perform the "Air Flap Position Learning" or "A/C Initialization" procedure to calibrate the air flap limit positions.
  • 9
    Refit all components. Start the vehicle and test the front passenger side temperature adjustment function through the full range (from lowest to highest temperature). Confirm the fault code does not recur.
Real-World Cases
BYD DTC AI Analysis

Deformed fuse holder pin caused loose connection to passenger side temperature control motor

✓
2018 Qin PRO DM. The customer reported the air conditioning operated only in face-vent mode with no ability to adjust temperature or airflow modes; the passenger side showed no temperature change. VDS read DTCs B2A2A14 (mode motor short to ground), B2A2C14 (passenger temperature control motor short to ground), and B2A2C92 (temperature control motor position not reached). Initial inspection revealed an aftermarket GPS unit tapping power from AC fuse IF03. After removing the added harness and replacing the fuse, the fault remained. Further measurement showed unstable supply voltage to the temperature control motor. Investigation found the fuse holder pins had spread from the use of a wider fuse blade during the GPS installation, causing poor contact. Technicians adjusted the fuse holder pin gap to restore clamping force, eliminating the fault.
Original source ↗
BYD DTC AI Analysis

Wiring harness chafed against steering column causing short to earth.

✓
A 2019 BYD Song MAX came in with an intermittent fault: the passenger-side AC temperature would not adjust while driving, working normally at times and failing completely at others. DTC B2A2C14 stored. The fault appeared intermittently during inspection. Removed the glove box and checked the passenger-side temperature blend motor. The connector had no backed-out pins, but measured abnormal voltage drop on the supply. Traced the wiring and found a retaining clip near the evaporator housing had detached, allowing the harness to chafe against the steering column over time. This wore through the insulation on the passenger-side temperature motor supply wire, causing an intermittent short to ground. Repaired the damaged wiring, re-insulated the harness, and secured the routing to prevent further interference. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Stuck air flap mechanism damaged the motor gear and set a short circuit fault.

✓
A 2017 Qin EV300 developed inoperative passenger-side vent temperature adjustment with the AC on, accompanied by distinct clicking. VDS showed DTCs B2A2C14 and B2A2C92 (temperature blend motor unable to reach position). Removing the passenger-side heater box revealed the temperature blend motor gear mechanism severely worn and seized. Manual actuation of the blend door linkage showed extreme resistance, with corrosion on the door shaft. Mechanical binding of the blend door caused continuous motor stall, excessive current draw triggering the short-to-ground protection (B2A2C14), while gear slippage created the clicking noise. Cleaned and lubricated the blend door linkage, replaced the passenger-side temperature blend motor assembly, and performed blend door position calibration. Temperature regulation returned to normal.
Original source ↗
Other Atto 3 Fault Codes
P0AA6Hybrid Battery Voltage System Isolation FaultB1108For 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.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.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.
Common problems reported for Atto 3 →Atto 3 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.