AU
B175B-00

DTC B175B-00 indicates the SRS (Supplemental Restraint System) control unit detects the right rear side airbag igniter circuit resistance (typically located in the right rear seat side or C-pillar trim panel) falls below the manufacturer threshold (normal range: 1 — Qin Plus

Safety System

DTC B175B-00 indicates the SRS (Supplemental Restraint System) control unit detects the right rear side airbag igniter circuit resistance (typically located in the right rear seat side or C-pillar trim panel) falls below the manufacturer threshold (normal range: 1.8–3.0 Ω; fault condition: below 1.0 Ω or near 0 Ω).

This constitutes a low-resistance airbag circuit fault, meaning the control unit identifies a short circuit risk (wiring harness short to ground, wire-to-wire short, or internal short within the airbag module).

Consequently, the affected side airbag may fail to deploy during a collision (as the ECU interrupts the trigger signal due to the circuit anomaly) or, in extreme cases, deploy unintentionally.

Simultaneously, the SRS system illuminates the instrument cluster airbag warning light and may disable the entire airbag system to protect occupants.

The B175B-00 fault code on the Qin Plus indicates a medium-severity SRS fault where the right rear side airbag igniter circuit resistance is too low, suggesting a short circuit risk. Common causes include an internally shorted right rear side airbag module or damaged wiring chafed to ground near the seat or body trim. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Right rear side airbag module internal igniter short circuit: Manufacturing defects, aging, or moisture ingress cause abnormally low resistance in the airbag internal igniter wire.
  • 2Wiring harness chafed and shorted to ground: Seat adjustment mechanism, seat belt anchor, or body sheet metal edge wears through the harness insulation, grounding the wire to the vehicle body.
  • 3Connector water ingress and corrosion: Vehicle wading, a blocked sunroof drain, or aging seals cause water to enter the airbag connector below the right B/C-pillar (usually located under the seat or at the base of the C-pillar). Electrolytic corrosion between the pins then creates a low-resistance path.
  • 4Improper seat modification or repair: When replacing seat covers, installing seat heaters, or adjusting the seat, fixing screws crush the wiring harness, or failing to fully lock the connector causes abnormal terminal contact.
  • 5SRS control unit internal sampling circuit fault: A fault in the ECU internal A/D converter or monitoring chip causes a false low resistance reading (less common; confirm after ruling out external wiring).
What To Do
  • 1
    Safety Preparation: Turn off the ignition switch, disconnect the 12V battery negative terminal, and wait at least 3 minutes (or follow workshop manual requirements to ensure the SRS capacitor discharges fully) to prevent accidental airbag deployment during repair.
  • 2
    Data confirmation: Connect the VDS2000/DiLink diagnostic tool, access the SRS system, and read the live data stream to confirm the right rear side airbag resistance is below the standard value (record the exact resistance value, such as 0.3Ω or 0.0Ω).
  • 3
    Visual inspection: Remove the right rear seat (if applicable) and lower C-pillar trim panel. Inspect the airbag wiring harness connector (usually a yellow plug) for looseness, water ingress, pin corrosion, or foreign objects.
  • 4
    Module isolation test: Disconnect the right rear side airbag connector. Connect a dedicated airbag simulator (resistor, usually 2.0 Ω) to the wiring harness side. Power on the vehicle and read the fault code. If the fault changes to 'open circuit' or the resistance is normal, the airbag module is faulty. If the resistance remains low, the wiring harness or ECU is faulty.
  • 5
    Harness continuity test: Disconnect the airbag module and SRS ECU connectors. Use a multimeter to measure the harness terminal-to-ground resistance (should be >1MΩ) and the resistance between the two harness wires (should be >1MΩ). Check for short circuits.
  • 6
    Wiring harness insulation check: Carefully inspect the wiring harness routing, especially where it passes through the seat frame and floor pan holes. Check for insulation damage. If necessary, repair the wiring harness and install corrugated conduit for protection.
  • 7
    Component replacement: If testing confirms an internal short circuit in the airbag module, replace the right rear side airbag module; if testing confirms a short circuit in the wiring harness, repair or replace the wiring harness; if testing confirms an ECU fault, replace the SRS control unit and perform coding matching.
  • 8
    System verification: After repair, clear the fault code, perform static and dynamic tests (including a simulated crash signal test to verify the system correctly identifies circuit status), and confirm the airbag warning light turns off normally.
Real-World Cases
BYD DTC AI Analysis

Right rear seat adjuster chafed through wiring harness, causing short circuit

✓
2017 BYD Qin EV300, 80,000 km. Airbag warning light on; DTC B175B-00. Inspection found the right rear seat rail wiring harness rubbing against the seat adjustment mechanism's metal edge. Long-term friction wore through the insulation, exposing two bare wires that contacted and shorted. Repair: Wrapped the damaged section with insulation tape, rerouted the harness, added corrugated tubing, and secured with cable ties to prevent interference with moving parts. Fault cleared.
BYD DTC AI Analysis

C-pillar connector corroded after water wading, causing low resistance

✓
Qin EV450 airbag warning light triggered after wading through heavy rain. Scan tool showed right rear side airbag resistance at 0.8Ω (low). Removed lower right C-pillar airbag connector and found water staining and green copper corrosion inside. Cause: Sunroof drain hose connector deteriorated and detached, letting rainwater run down the A-pillar, across the floor and into the C-pillar. Repair: Cleaned connector pins with electrical contact cleaner, applied conductive protective grease, repaired the drain hose. Cleared fault codes; no recurrence.
BYD DTC AI Analysis

Loose connector after accident repair causes intermittent fault

✓
After repairing a right rear side collision on a Qin 100, the dashboard intermittently displayed an airbag fault. Testing revealed intermittent DTC B175B-00. Inspection found technicians had replaced the right rear side airbag during the accident repair, but the connector locking tab had not fully engaged. Vehicle vibration caused poor terminal contact, with resistance fluctuating between 0.5 and 2.0 Ω. After reseating the connector and confirming the locking tab clicked into place, the data stream showed stable resistance at 2.2 Ω and the fault resolved.
BYD DTC AI Analysis

Airbag module requires replacement due to internal igniter short circuit

✓
A 2018 Qin EV300 showed persistent DTC B175B-00. Disconnected the airbag module and connected a simulator to the harness; the DTC changed to open circuit (normal). Harness insulation to ground measured good. Measured the airbag module resistance separately: 0.2Ω, well below the 2.0Ω standard. Determined the airbag igniter was internally shorted. Replaced the right rear side airbag module (required new mounting bracket and bolts), performed system configuration write, and cleared the fault.
BYD DTC AI Analysis

Aftermarket seat heating pad installation pinched wiring harness

✓
A Qin 80 owner reported an illuminated airbag warning light after installing an aftermarket seat heater. Inspection found that while drilling into the right rear seat foam to route wiring, the installer used screws that were too long, piercing the harness sheath and shorting the airbag harness positive and negative leads. Replaced the damaged harness section (severe internal damage required replacing the entire section). Rerouted the wiring to avoid the heating elements. Fault resolved.
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.