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 8

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.

The B1737 fault code on the Atto 8 indicates a high-severity SRS fault where the right middle-row side airbag circuit may be shorted to battery power. This can stop the airbag deploying correctly and may create a safety risk. Common causes include damaged seat airbag wiring or corrosion/water ingress in the yellow airbag connector. Do not inspect the airbag yourself; visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Right middle-row seat side airbag wiring harness worn or insulation damaged, causing a short circuit to a body permanent live circuit (such as seat heater or adjustment motor power supply wires).
  • 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 terminal and the airbag circuit terminal.
  • 3Internal igniter in the right middle-row side airbag assembly (curtain or seat airbag) shorted to power. Internal airbag module manufacturing defects or previous external impacts typically cause this.
  • 4Mistakenly connecting the airbag wiring harness in parallel with the 12V power supply wire during vehicle modification (such as installing seat ventilation, heating, or ambient lighting), or damaging the wiring harness during drilling.
  • 5Internal driver/monitoring circuit fault in the airbag control module (SRS ECU) causing false detection of a short to power in the right middle-row side airbag circuit.
What To Do
  • 1
    Safety preparation: Switch the vehicle to OFF, disconnect the 12V battery negative terminal and wait at least 90 seconds (to fully discharge the SRS backup power capacitor). Do not measure airbag terminals directly with a multimeter.
  • 2
    Fault confirmation: Use VDS or the BYD dedicated diagnostic tool to read DTC B1737 and freeze frame data. Record parameters such as vehicle speed and temperature when the fault occurred. Confirm the current fault is not a historical fault.
  • 3
    Visual Inspection: Inspect the yellow wiring harness located at the side of the right middle-row seat (if a side airbag label is present), the lower B-pillar trim panel, and near the seat rail for wear, pinching, water stains, or signs of modification.
  • 4
    Connector inspection: Disconnect the right middle-row side airbag connector (usually a yellow plug with a shorting spring) and inspect the terminals for burn marks, corrosion, or short circuits caused by foreign objects.
  • 5
    Circuit isolation test: Use a multimeter to measure voltage to ground and voltage 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 abnormal voltage or resistance exists between the side airbag assembly terminals 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), 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 8 Fault Codes
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.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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.