AU
B1737

DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive) — Atto 3

Safety System

DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive).

The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω).

If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power.

This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current.

In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Worn right middle row seat side airbag wiring harness or damaged insulation causing a short circuit to a body constant power circuit (such as seat heating or seat adjustment motor power supply lines).
  • 2Water ingress, corrosion, or deformed terminals in the yellow airbag connector under the seat or inside the B-pillar trim, causing a short circuit between the power supply terminal and the airbag circuit terminal.
  • 3Internal igniter in the right middle row side airbag assembly (curtain or seat airbag) shorted to power. An internal manufacturing defect in the airbag module or a previous external impact usually causes this.
  • 4Mistakenly connecting the airbag wiring harness in parallel with the 12V power supply wire during vehicle modifications (such as adding seat ventilation, heating, or ambient lighting), or damaging the wiring harness during drilling.
  • 5Airbag control module (SRS ECU) internal driver/monitoring circuit fault causing false detection of a short to power in the right middle-row side airbag circuit.
What To Do
  • 1
    Safety preparation: Turn the vehicle OFF, disconnect the 12V battery negative terminal, and wait at least 90 seconds (to ensure the SRS backup power capacitor fully discharges). Do not measure the airbag terminals directly with a multimeter.
  • 2
    Fault Confirmation: Use VDS or a BYD dedicated diagnostic tool to read DTC B1737 and freeze frame data. Record parameters such as vehicle speed and temperature at the time of the fault. Confirm the current fault is not a historical fault.
  • 3
    Visual inspection: Inspect the yellow wiring harness at the side of the right middle-row seat (if a side airbag label is present), under the lower B-pillar trim panel, and near the seat rails for wear, crushing, water stains, or signs of modification.
  • 4
    Connector check: Disconnect the right middle row side airbag connector (usually a yellow plug with a shorting spring plate). Check the terminals for burning, corrosion, or short circuits caused by foreign matter.
  • 5
    Circuit isolation test: Use a multimeter to measure voltage to ground and to power at the airbag harness side (non-airbag end). A 12V reading confirms a short to power. Use the multimeter resistance setting to measure continuity between this circuit and a known power supply harness to locate the short.
  • 6
    Harness routing inspection: Inspect the harness routing from the right middle-row seat to the SRS ECU (typically routed through the floor harness and B-pillar). Check specifically for harness wear in the seat slide rail movement area and under the door sill trim plate.
  • 7
    Component replacement: If the wiring harness is damaged, repair the insulation or replace the wiring harness. If the side airbag assembly terminals show abnormal voltage or resistance after disconnecting the wiring harness, replace the right middle-row side airbag assembly. If the wiring harness is normal but the fault persists, consider replacing the SRS ECU.
  • 8
    System verification: After repair, reconnect all connectors (listen for the locking click) and connect the battery. Use the diagnostic tool to clear the fault code and perform an SRS system self-test. Confirm B1737 does not return and the airbag warning light turns off.
Real-World Cases
BYD DTC AI Analysis

BYD Song MAX: Right-hand second-row seat runner chafed the wiring harness, causing a short circuit.

✓
A 2019 Song MAX with 32,000 km on the clock had a steady airbag warning light on the instrument panel. VDS retrieved fault code B1737 (right second-row side airbag short to power), which would not clear. Technicians removed the right second-row seat and found that the seat rails had been rubbing against the wiring harness near the yellow airbag connector underneath, wearing through the insulation. The exposed wire contacted the seat heater constant power wire (always live), creating a short to power. They repaired the damaged harness with heat shrink tubing, rerouted the wiring to clear the seat rail travel area, and added corrugated tubing protection. This resolved the fault.
Original source ↗
BYD DTC AI Analysis

BYD Tang DM: Right second-row side airbag connector shorted due to water ingress after wading

✓
2021 Tang DM. After wading through about 40 cm of water, multiple warning lights came on the dash, with the airbag light staying on constantly. The scan tool showed active fault code B1737. Inspection found wet carpet beneath the right middle-row seat. Disassembling the airbag connector revealed standing water and verdigris inside; the terminals had shorted to power due to water conductivity. Further testing found degraded insulation in the SRS ECU-to-airbag wiring at the floor level. Repair: dried the interior thoroughly, cleaned the connector with electronic cleaner, replaced the wiring harness assembly beneath the right middle-row seat (including the airbag connector), and waterproofed the harness.
Original source ↗
BYD DTC AI Analysis

BYD Yuan EV right middle row side airbag internal igniter short circuit

✓
2019 Yuan EV, 8,000 km, no collision or water ingress history. Airbag warning light suddenly illuminated. Retrieved DTC B1737. Disconnected the right second-row seat side airbag connector. Measured harness side – no short to power. Measured airbag assembly (integrated into seat) resistance between terminals: 0.5 Ω, and detected 12V to the metal bracket. Determined the airbag internal igniter had shorted to power. Root cause: internal manufacturing defect in the airbag assembly or damage during transport/installation. Replaced the right second-row seat side airbag assembly. System returned to normal.
Original source ↗
BYD DTC AI Analysis

BYD Qin Pro leather seat modification damaged the airbag wiring harness

✓
2020 BYD Qin petrol. After an aftermarket leather seat upholstery job, the airbag warning light came on immediately at startup. VDS scan revealed DTC B1737. Inspection found that during removal and reinstallation of the right middle-row seat, a tool pierced the side airbag harness on the seat, causing a short between the airbag igniter circuit and the aftermarket seat heating circuit (which was powered from a constant battery tap). Because of the aftermarket work, the dealership refused warranty. Repair: Soldered the damaged airbag harness and sealed the repair with double-layer heat shrink tubing, disconnected the incorrect seat heating power tap, restored the factory wiring routing, and cleared the fault code.
Original source ↗
BYD DTC AI Analysis

BYD Tang SRS ECU internal circuit fault falsely reports DTC B1737

✓
2021 Tang – intermittent airbag warning light. Retrieved DTC: intermittent B1737. Checked right second-row side airbag wiring harness, connectors, and airbag assembly multiple times — found no faults. Wiring insulation intact, no short to power. Measured drive circuit from SRS ECU to airbag per wiring diagram; when fault occurred, ECU output terminal showed 12V abnormally. Determined internal monitoring circuit or driver chip failure in airbag control module causing false short-to-power detection. Replaced SRS ECU (required VIN coding and calibration data reconfiguration). Fault eliminated.
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.