AU
B1730

DTC B1730 indicates the airbag control unit (SRS ECU) detects a resistance of 0 ohms in the left second-row side airbag firing circuit (typically located inside the left B-pillar trim or on the side of the left second-row seat) — Qin Plus

Safety System

DTC B1730 indicates the airbag control unit (SRS ECU) detects a resistance of 0 ohms in the left second-row side airbag firing circuit (typically located inside the left B-pillar trim or on the side of the left second-row seat).

This indicates a short to ground in the firing circuit, damaged wiring harness insulation shorting to ground, or an internal short circuit in the airbag module inflator.

This fault forces the SRS system into fail-safe mode, preventing the left second-row side airbag from deploying during a side impact, and continuously illuminates the instrument cluster airbag warning light.

Unlike high resistance (open circuit), a 0-ohm resistance typically means current flows directly to ground without passing through the inflator.

This is a hard short circuit fault and requires immediate repair.

The B1730 fault code on the Qin Plus indicates a short to ground in the left second-row side airbag firing circuit. Severity is medium, but it needs prompt attention because the SRS system may enter fail-safe mode and the left side airbag may not deploy in a side impact. Common causes include a faulty airbag igniter or water-damaged/bent connector pins. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Left middle row side airbag module internal igniter short circuit (manufacturing defect, moisture ingress, or aging causing an internal bridge wire short circuit)
  • 2Water ingress or bent pins at the airbag wiring harness connector (poor B-pillar trim panel sealing commonly allows rainwater to seep in, causing a short circuit between connector terminals or to ground)
  • 3Wiring harness wear causing a short to body ground (frequent seat adjustment, B-pillar trim removal/installation, or modifications pinch the harness and wear through the insulation).
  • 4Improper installation of aftermarket accessories or modifications (e.g., fasteners piercing the wiring harness when installing seat covers or floor liners, or incorrect wire tapping when adding seat heating or ventilation systems)
  • 5SRS control unit internal detection circuit fault (uncommon; damaged control unit A/D conversion circuit causes a false 0 resistance reading)
What To Do
  • 1
    Safety preparation: Power down the vehicle, disconnect the battery negative terminal, and wait at least 90 seconds to fully discharge the SRS backup power supply and prevent accidental airbag deployment.
  • 2
    Fault Confirmation: Use VDS or a dedicated diagnostic tool to read the fault code. Confirm B1730 is a current fault and will not clear. Record freeze frame data to check vehicle status when the fault occurred.
  • 3
    Visual inspection: Remove the left middle-row B-pillar lower trim panel or seat side cover. Check the airbag connector (usually yellow) for water ingress, corrosion, deformed pins, or looseness. Check the wiring harness for damage or crush marks.
  • 4
    Resistance measurement: Disconnect the airbag module connector. Use a digital multimeter to measure the resistance between the two terminals on the airbag module side. The standard value is 2.0-3.0 Ω. If the resistance is 0 Ω or close to 0 Ω, replace the airbag module.
  • 5
    Harness insulation check: Disconnect the SRS control unit connector and measure the resistance between the harness-side airbag circuit and body ground. Resistance must be greater than 1MΩ. If the resistance is too low, inspect the harness in sections, focusing on the harness routing inside the B-pillar trim panel and at the seat slide rail.
  • 6
    Short circuit point repair: Upon finding wiring harness damage, repair using heat-shrink tubing or insulating tape. Replace the wiring harness assembly if necessary. Ensure sufficient clearance between the wiring harness and vehicle body metal parts, and install a protective sleeve.
  • 7
    Reassembly and verification: Reconnect all connectors (ensure an audible click), reconnect the negative battery terminal, and clear the fault code. Turn the ignition switch to the ON position, verify the instrument cluster airbag warning light turns off after 6 seconds, and perform an SRS system self-diagnosis to confirm no faults exist.
Real-World Cases
BYD DTC AI Analysis

Tang DM left second-row side airbag short circuit after wading through water

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Vehicle: 2021 BYD Tang DM. Symptom: The airbag warning light on the dashboard stayed on after the vehicle drove through water. Diagnosis: Connected VDS and retrieved DTC B1730 (current fault). Removed the left B-pillar lower trim panel and found the airbag connector (yellow plug) had visible water stains and verdigris corrosion inside. Resistance between the pins measured 0.2 Ω, forming a short circuit. Further inspection found the B-pillar weatherstrip had perished, letting rainwater in. Solution: Cleaned the connector thoroughly with electronic contact cleaner, dried it with compressed air, and applied conductive grease to prevent corrosion. Replaced the left second-row side airbag module (the old one had moisture damage). Repaired the B-pillar weatherstrip. Road tested for one week with no fault recurrence.
BYD DTC AI Analysis

Seat modification damaged wiring harness on Song MAX

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Vehicle: 2019 Song MAX. Symptoms: Airbag warning light came on the day after installing leather seat covers. Diagnosis: Read DTC B1730. Asked the owner and confirmed the recent seat cover installation. Removed and inspected the left middle row seat. Found the metal retaining ring for the seat cover had pierced the side airbag wiring harness, causing the ignition wire to short directly to ground on the seat frame. Repair: Cut out the damaged section and soldered in a replacement length of high-temperature insulated wire (cross-sectional area ≥0.5 mm²). Rewrapped with insulating tape, fitted corrugated tubing for protection, and rerouted the harness clear of the clip position. Cleared the fault codes and the system returned to normal.
BYD DTC AI Analysis

Internal short circuit in a batch of Yuan EV airbag modules

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Vehicle: 2019 BYD Yuan EV535. Symptoms: No accident history; airbag warning light suddenly illuminated during normal use. Diagnosis: DTC B1730. Resistance at the airbag module connector measured only 0.8Ω, well below specification (2.0–3.0Ω). With the module disconnected, wiring harness insulation to earth tested normal. Confirmed internal short circuit in the module. This production batch has a common quality defect. Repair: Ordered and replaced the left second-row side airbag module (part number requires VIN verification). After fitting the new module, resistance measured 2.4Ω. Cleared DTC and completed system configuration. Fault fully resolved.
BYD DTC AI Analysis

Qin Pro intermittent short circuit on rough roads

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Vehicle: 2020 Qin Pro (petrol) Symptoms: Airbag warning light occasionally illuminated on rough roads; functioned normally on smooth surfaces. Diagnosis: DTC B1730 indicated an intermittent fault. Static resistance measured normal. Flexing the wiring harness to simulate driving conditions revealed an improperly seated airbag connector under the left seat of the middle row. During driving on bumpy roads, the yellow connector housing contacted the body metal bracket, causing an intermittent short to ground. Repair: Re-seated the connector and ensured the locking tab fully engaged. Secured the wiring harness to the seat frame with cable ties to prevent movement. Wrapped insulating tape around the connector housing for added protection. Follow-up: No recurrence after one month.
BYD DTC AI Analysis

Tang II SRS control unit software false alarm

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Vehicle: 2021 Tang DM-i. Fault: After accident repair (left rear quarter panel sheet metal work), persistent DTC B1730. Replacing the airbag module did not fix it. Diagnosis: Measured new module resistance at 2.2 Ω (normal). Wiring harness insulation to earth normal. Suspected control unit issue. Checked technical service bulletin – this production batch had a software calibration defect, causing false low-resistance detection in cold temperatures. Solution: Updated SRS control unit software to latest version (V2.1 or above), performed sensor calibration, and cleared fault codes. Fault resolved, no hardware replacement needed.
Other Qin Plus Fault Codes
B1108For 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.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Qin Plus →Qin Plus 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.