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B132013

DTC B132013 is a specific fault within the thermal management/air conditioning subsystem (13) of the BYD body control system (B-Body) — Atto 3

Thermal Management System

DTC B132013 is a specific fault within the thermal management/air conditioning subsystem (13) of the BYD body control system (B-Body).

The '20' designates the battery coolant temperature sensor or a related thermal management temperature sensor, and '13' indicates an open circuit.

This fault indicates the thermal management control unit (typically integrated into the Battery Management System (BMS) or air conditioning controller) detects a continuously high voltage on the coolant temperature sensor signal circuit (typically near the 5V reference voltage) and cannot obtain a valid temperature resistance signal.

As a result, the thermal management system enters fail-safe mode.

The system forcibly limits charge and discharge power, disables DC fast charging, and activates the maximum cooling strategy (high-speed fan and full-speed water pump operation).

In extreme cases, the system triggers a 'powertrain fault' and prevents the vehicle from entering the Ready state to prevent overheating damage to the battery or drive motor caused by the loss of temperature monitoring.

4
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1The NTC thermistor element inside the sensor body is broken or open, causing infinite resistance (normal resistance at room temperature is 2kΩ-10kΩ, depending on the model-specific calibrated temperature curve).
  • 2Loose low-voltage wiring harness connector, backed-out terminals, or oxidized/corroded pins. Vibration or water ingress causes poor contact, especially at the low-voltage plug near the battery pack high-voltage connector.
  • 3Physical damage to the wiring harness, including insulation aging and cracking due to high temperatures in the front compartment, harness chafing against body panels, or rodents chewing through the signal wire.
  • 4Sensor power supply or ground circuit fault, such as a short to ground in the 5V reference voltage circuit causing a protective ECU cutoff, or the ECU misinterpreting excessive ground return circuit resistance as an open circuit.
  • 5Internal signal acquisition circuit fault in the thermal management control unit (BMS or air conditioning controller), such as a burnt sampling resistor or damaged analog-to-digital converter.
What To Do
  • 1
    Use VDS or a dedicated diagnostic tool to read the DTC freeze frame data. Record the ambient temperature, battery temperature, and vehicle status when the fault occurred. Confirm whether it is a hard fault (currently present) or an intermittent fault (history code).
  • 2
    Visually inspect the coolant temperature sensor connector at the battery pack coolant outlet, PTC heater outlet, or plate heat exchanger outlet. Confirm the connector lock is intact, secure, and shows no signs of water ingress or corrosion. If necessary, disconnect the connector and check for backed-out terminals.
  • 3
    Disconnect the sensor connector and measure the sensor body resistance with a multimeter. At 25°C ambient temperature, normal resistance is approximately 10 kΩ (refer to the temperature-resistance curve table in the repair manual). If the reading is infinite (OL), replace the sensor.
  • 4
    Keep the connector disconnected and measure the voltage at the wiring harness side: it must show a 5V reference voltage (Vref) and 0V ground, and the signal wire voltage must be approximately 5V (open-circuit voltage). If the voltages are incorrect, check wiring harness continuity between the sensor and the control unit, especially the harness passing through the front compartment and battery pack area.
  • 5
    Perform continuity and insulation tests on the wiring harness: measure the signal wire resistance between the sensor connector and the control unit connector. The resistance must be less than 1Ω, and the insulation resistance to ground must be greater than 10MΩ. Closely inspect the wiring harness bend points where it passes through the firewall and battery pack casing.
  • 6
    Sensor replacement verification: Perform a jumper test using a known-good sensor of the same model. Observe if the data stream returns to normal. If normal, the original sensor is faulty.
  • 7
    After repairing the wiring harness or replacing the sensor, clear the fault code and perform a road test (including different vehicle speeds and charge/discharge conditions). Monitor the thermal management data stream to verify the temperature reading changes smoothly with operating conditions, confirming complete fault resolution.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Qin EV300: Loose battery pack connector caused intermittent open circuit

✓
A 2017 Qin EV300 with 80,000 km had an intermittent “Power System Fault”, especially after driving on rough roads. The scan tool showed current fault code B132013. Inspection of the coolant temperature sensor plug at the front of the battery pack revealed a broken lock clip. This prevented the connector from seating fully, and it would disconnect with slight vibration. Replaced the waterproof plug housing (complete with lock clip), re-crimped the harness terminals, and applied BYD conductive paste (Kontakt 61). Fault completely resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

Front compartment wiring harness chafed against bracket, causing signal wire to break

✓
After collision repair, fault code B132013 persisted and could not be cleared. Inspection found the wiring harness had been improperly secured during the accident repair, causing the battery cooling system water temperature sensor harness to chafe against the front chassis rail bracket. Prolonged friction broke a single copper strand, while the outer insulation remained intact, creating a hidden open circuit. Repair: Stripped back the harness insulation to locate the break. Repaired the wiring using waterproof heat-shrink tubing. Rerouted the harness, added corrugated tubing for protection, and secured it in the original factory clip positions.
BYD DTC AI AnalysisFrom Chinese market (translated)

Sensor thermal aging caused an open circuit under high-temperature operating conditions.

✓
The vehicle developed a fault after running the PTC heater for a while in winter, although cold starts were normal. When the sensor was heated with a heat gun, its resistance suddenly jumped to open circuit at about 60°C and recovered after cooling. This indicates thermal fatigue fracture of the internal NTC element. Replacing the battery coolant temperature sensor (part no. BYD-3726010-XX) fixed the fault. Also check whether degraded coolant is causing abnormal heat transfer to the sensor.
BYD DTC AI AnalysisFrom Chinese market (translated)

Connector pins oxidised after water ingress, causing excessive contact resistance

✓
After driving through water, the vehicle developed a fault. The scan tool showed the coolant temperature sensor signal voltage was 4.9V (near the open circuit threshold). We disconnected the coolant temperature sensor connector under the battery pack and found mud and water had gotten inside. The pins were oxidised and blackened, creating high resistance that caused the control unit to misinterpret the condition as an open circuit. We thoroughly cleaned the connector with electronic cleaner, sanded the pins down to bare metal, and applied a protective coating. We also replaced the sealing ring and, where needed, applied sealant around the connector to improve waterproofing.
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. Sources: [1]