AU
B132213

This fault code indicates an open circuit in the signal circuit of the pressure/temperature sensor at the Plate Heat Exchanger (PHE) outlet — Atto 3

Thermal Management System

This fault code indicates an open circuit in the signal circuit of the pressure/temperature sensor at the Plate Heat Exchanger (PHE) outlet.

In the BYD heat pump thermal management system, the Plate Heat Exchanger is the core component for heat exchange between the refrigerant and the motor coolant.

The outlet pressure sensor monitors the refrigerant pressure (or integrated temperature) after heat exchange, providing closed-loop control data for the Electronic Expansion Valve (EXV) and the electric compressor.

An open circuit fault indicates the control unit (air conditioning controller or thermal management module) detects a continuous sensor signal voltage above 4.8V (typically corresponding to an unshunted 5V reference voltage).

Without real-time pressure data, the system triggers thermal management protection mode.

This mode disables the heat pump function, limits motor power output, and in extreme cases, prohibits high-voltage power-up to prevent heat exchanger overpressure damage or abnormal refrigerant circulation.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Physical damage to the sensor wiring harness: High temperatures and vibration in the motor compartment cause the harness insulation to age and crack, or prolonged friction against sharp metal edges breaks the copper core wires. This commonly results from improper harness securing after accident repairs.
  • 2Poor connector contact: Internal terminals in the 2-pin or 3-pin sensor connector backed out or oxidized (common after water ingress), or loose retaining clip. This causes an open signal circuit, measuring as infinite resistance between pins.
  • 3Internal open circuit in the sensor body: Refrigerant pressure shock or long-term thermal cycling fatigue cracks solder joints on the pressure-sensitive element or internal PCB, resulting in zero current draw.
  • 4Control unit fault: A loose connector, bent pins, or an open internal sampling resistor at the A/C controller or thermal management controller (TMS) prevents the 5V reference voltage from completing a circuit.
  • 5Wiring harness transition connector fault: Some models have a transition connector (CJB or BJB) at the firewall or fender. Poor sealing at this location causes water ingress and corrosion, resulting in an open circuit in the signal wire at the transition point.
What To Do
  • 1
    Safety preparation and fault confirmation: Disconnect the high-voltage service disconnect and wait 5 minutes to discharge residual voltage; use the diagnostic tool to read the DTC and record the freeze frame data, and observe the pressure display value (an open circuit typically displays 4.9-5.0V or an out-of-range value of -40°C); clear the fault code, run the air conditioning system, and observe if the fault recurs immediately.
  • 2
    Sensor body inspection: Locate the pressure and temperature sensor at the plate heat exchanger outlet (usually on the top or side of the heat exchanger, with a 2-3 wire harness). Disconnect the connector and measure the resistance between the sensor terminals (normally about 2-3 kΩ at 25°C; refer to the workshop manual for exact values). If the resistance is infinite, replace the sensor. Measure the supply voltage (must be 5V ± 0.25V) and confirm normal reference voltage output.
  • 3
    Wiring harness continuity check: Use a multimeter to measure wiring harness continuity between the sensor connector and the control unit, focusing on the signal wire (usually the pressure signal pin) and the ground wire; check the entire harness for signs of crushing or abrasion, especially where it passes through the firewall and high-temperature areas near the exhaust pipe; measure the harness insulation resistance to ground, which must be greater than 10MΩ.
  • 4
    Connector integrity repair: Check if the connector sealing ring is missing or aged, and replace the waterproof plug if necessary. Use a dedicated terminal removal tool to check terminal retention force. Replace the connector assembly or female terminal if loose. Clean oxidized pins, apply conductive grease, and reconnect until a locking click is heard.
  • 5
    System verification and completion: After repair, reconnect all components, power on the vehicle, and read the data stream. Confirm the displayed pressure matches the actual ambient temperature (static pressure approximately 0.6-0.8MPa@25℃). Start heat pump mode and observe the dynamic pressure response as the electronic expansion valve opening changes. Perform a road test or hoist test and confirm no intermittent open circuits exist before vehicle handover.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Intermittent open circuit in plate heat exchanger pressure sensor on Qin Pro DM after wading

✓
The air conditioning stopped producing heat after the vehicle drove through water. DTC B132213 stored. Inspection revealed water inside the plate heat exchanger outlet pressure sensor connector, with the pins oxidised and blackened. The connector seal failed due to water surge while wading. Cleaned the oxidised pins, replaced the seal, and fitted waterproof corrugated tubing to the wiring harness. Fault resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

Qin EV300: Wiring harness wear caused open circuit after accident repair

✓
Following right-front collision repairs, B132213 would set intermittently while driving. Inspection found the accident repair had incorrectly secured the harness, causing the plate heat exchanger sensor wiring to chafe against the sharp edge of the right front chassis rail. The insulation wore through and the signal wire (one of three copper cores) completely fractured. Repaired the damaged harness, sealed with heat shrink tubing, re-routed and secured the clips to specification, and fitted a protective sleeve to prevent chafing.
BYD DTC AI AnalysisFrom Chinese market (translated)

False open circuit caused by a loose thermal management controller connector

✓
Vehicle has no accident history. Heat pump system suddenly failed. Diagnostics showed the pressure sensor had normal power supply but the signal voltage remained at 5V. Investigation revealed the 32-pin connector on the thermal management controller (under the centre console) was not fully locked, possibly loosened when stepped on during transport or repairs. Reseated and secured the connector; fault cleared.
BYD DTC AI AnalysisFrom Chinese market (translated)

Cracked internal PCB in sensor body caused open circuit at low temperatures

✓
In cold northern winter weather, the vehicle could not start the heat pump; the fault disappeared in a warm garage. Disassembly revealed that the internal PCB solder joint of the plate heat exchanger outlet pressure sensor cracked due to low-temperature contraction, causing a signal open circuit. Replaced the OEM pressure-temperature sensor assembly and verified the fault was cleared in a -20°C environmental chamber.
BYD DTC AI AnalysisFrom Chinese market (translated)

Hidden open circuit caused by water ingress and corrosion in the adapter plug

✓
DTC appeared intermittently. Tapping the inner fender wiring harness reproduced the fault. Inspection found water ingress at the firewall connector (BJ02) due to perished sealing rubber. The pressure sensor signal wire had corroded and broken at the connector terminal. Replaced the connector assembly, repaired the corroded wiring harness, and resealed the firewall penetration with sealant.
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]