AU
B2A3314

DTC B2A3314 indicates a short to ground or open circuit in the Front Left Corner Sensor signal circuit — Atto 3

Thermal Management System

DTC B2A3314 indicates a short to ground or open circuit in the Front Left Corner Sensor signal circuit.

This fault code belongs to the Park Assist System (APA) / Around View Monitor (AVM) system, not the thermal management system.

The APA control module sets this fault when it detects the Front Left Corner Sensor signal voltage remains below 0.5V (short to ground) or above 4.5V (open circuit) for more than 500ms.

This fault causes front left obstacle detection failure, potentially triggering false park assist warnings or complete loss of function.

The system classifies this as a severe fault because it may affect Automatic Emergency Braking (AEB) operation in extreme cases.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Radar sensor internal coil open or short circuit, typically resulting from physical impact, aging, or internal water ingress due to seal failure.
  • 2Wiring harness chafing or pinching causes the signal wire to short to ground or open circuit. Common locations include where the front bumper harness passes through the wheel arch, side member, or front compartment firewall.
  • 3Loose sensor connector, corroded pins, or aged and failed sealing ring, especially common after water wading, car washing, or exposure to high-humidity environments.
  • 4APA control module internal signal processing circuit fault; unable to correctly receive or interpret the left front radar signal.
  • 5Improper vehicle modifications (such as installing a dash cam, modifying the front bumper, or applying film) resulting in a cut or crushed wiring harness, or incorrect sensor installation.
What To Do
  • 1
    Use the dedicated BYD VDS2000 diagnostic tool to read fault codes, confirm if B2A3314 is a current fault, and check for related history fault codes (e.g., U024587 communication fault).
  • 2
    Visually inspect the left front radar sensor to verify the probe surface is free of scratches or deformation, the installation gap meets the standard (0.5-1.0mm), and the bumper shows no signs of modification.
  • 3
    Disconnect the sensor connector and measure the power supply pin voltage (should be 12V±0.5V), the ground pin resistance (should be less than 1Ω), and the signal wire-to-ground resistance (normally greater than 10kΩ; close to 0Ω if shorted).
  • 4
    Inspect the left front radar wiring harness along its routing. Focus on wear-prone areas such as the inside of the wheel arch, the front longitudinal beam, and below the A-pillar. Check for signs of harness damage, chafing, or breaks.
  • 5
    Inspect the APA control module connector (usually located in the boot or under the dashboard) for water ingress, corrosion, or looseness.
  • 6
    Replace the faulty component based on the measurement results: if the sensor is faulty, replace the radar sensor (e.g., part number 5A-3600600); if the wiring harness is faulty, repair or replace the wiring harness; if the module is faulty, replace the APA control module.
  • 7
    After repair or replacement, clear the fault code. Use the diagnostic tool to perform the 'Parking Assistance System Configuration' and 'Radar Sensor Calibration' procedures to correctly write the detection distance and angle parameters for all sensors.
  • 8
    Perform a road test to verify normal operation of the radar during low-speed driving, the warning tone when engaging reverse gear, and the center console radar display. Confirm the fault code does not recur.
Real-World Cases
BYD DTC AI Analysis

BYD Song Pro DM left front radar failure (wiring harness chafed, shorted)

✓
Symptoms: After starting the vehicle, the instrument cluster displayed 'Parking Assist System Fault'. When reverse was engaged, the reversing camera functioned normally but the parking radar provided no audible warnings. The center screen showed a red exclamation mark at the left-front radar position. Diagnosis: Connected VDS2000 and retrieved DTC B2A3314. Measured the sensor connector and found 0Ω resistance between the signal wire and ground. Inspection revealed the left-front wheel arch harness had been chafed through by an aftermarket dash cam harness, causing the signal wire to short to ground. Resolution: Repaired the damaged harness and re-insulated it. Rerouted the dash cam wiring to prevent contact. Cleared the DTCs and recalibrated the radar system.
Original source ↗
BYD DTC AI Analysis

BYD Han EV: Intermittent front radar failure (connector seal perished)

✓
Symptoms: Intermittent long "beep" alarm during normal driving (no obstacles ahead). Left front radar detection range is severely reduced when parking (normal 2.5 m, actual 0.8 m). Fault occurs more frequently after rain or washing. Diagnosis: Codes B2A3314 (history) and B2A3315 (current). Checked the left front radar connector: signal line tested normal at ambient temperature, but shorted intermittently when wiggling the harness. The connector seal ring had aged, letting moisture in and corroding the pins. Fix: Replaced the left front radar sensor assembly and waterproof seal ring. Applied conductive grease to the pins and resealed the connector. Fault eliminated.
Original source ↗
BYD DTC AI Analysis

Tang DM-i parking system false alarms (broken wiring harness after accident)

✓
Symptoms: Left front radar continuously alarmed showing 0.3m distance while stationary (no obstacle present), with occasional false AEB triggering while driving. Instrument cluster displayed "Check Parking Assist System". Diagnosis: Dealership read DTCs B2A3314 and U024587 (APA module communication fault). Left front radar calibration failed. Measured the harness between the APA module and left front radar and found the signal line open. Disassembly found accident repairs had left the wiring harness inside the left front side member unsecured, allowing it to chafe against the body metal edge and break. Fix: Repaired the harness and added corrugated tubing for protection. Replaced the APA control module damaged by repeated short circuits. Performed system calibration and eliminated the fault.
Original source ↗
BYD DTC AI Analysis

Qin Plus DM-i radar fault after modification (physical damage to sensor)

✓
Symptoms: After the owner fitted an aftermarket front bumper, the dashboard displayed a 'Parking Assist System Fault' warning. When reversing, none of the parking sensors produced audible alerts. The diagnostic tool logged DTCs B2A3314 (left front) and B2A3414 (right front). Diagnosis: Inspecting the modified front bumper revealed the sensor mounting holes did not align with factory specifications. Over-tight installation had compressed and deformed the left front sensor; internal coil resistance measured infinite (internal open circuit), and the wiring harness plug was loose. Solution: Replaced the left and right front parking sensors. Reworked the front bumper mounting holes to ensure correct sensor fitment and clearance. Reconnected the plugs securely and performed system configuration and calibration.
Original source ↗
BYD DTC AI Analysis

Yuan Plus radar signal anomaly (software bug)

✓
Symptoms: One week after delivery, the left front radar occasionally emitted a continuous tone. The fault mainly occurred after high-temperature sun exposure. DTCs B2A3314 and B2A3311 (signal short to power) set, sometimes clearing after a restart. Diagnosis: The 4S shop inspected the wiring harness and found no abnormalities. Measuring the left front radar signal waveform against a normal vehicle revealed low amplitude and noise. Replacing the sensor did not resolve the fault. The APA control module was running outdated software (not the latest V2.3.5), which contained a signal processing bug. Resolution: Upgraded the APA control module software to the latest version and performed sensor calibration and learning. Monitored for one month in high-temperature conditions; the fault has not reoccurred.
Original source ↗
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.