AU
B175212

DTC B175212 indicates the Supplemental Restraint System (SRS) detects abnormal continuity between the ignition circuit of the right rear side airbag (Side Airbag Module, typically installed inside the C-pillar trim panel or on the side of the seat backrest) and the vehicle power supply positive (B+) — Atto 8

Safety System

DTC B175212 indicates the Supplemental Restraint System (SRS) detects abnormal continuity between the ignition circuit of the right rear side airbag (Side Airbag Module, typically installed inside the C-pillar trim panel or on the side of the seat backrest) and the vehicle power supply positive (B+).

In the SRS architecture, the airbag squib circuit must maintain high-resistance isolation from both power and ground.

When the ECU detects that the circuit voltage continuously exceeds the threshold (typically over 80% of supply voltage) and the resistance falls below the specified value (<1kΩ), it identifies a short to power.

This fault may cause: 1) Airbag deployment failure during a collision (ECU triggers protective cut-off). 2) Accidental airbag deployment in extreme cases due to false triggering. 3) SRS fail-safe mode activation, limiting overall vehicle airbag functions.

The B175212 fault code on the Atto 8 indicates a high-severity SRS fault where the right rear side airbag ignition circuit may be shorted to battery power. This can stop the airbag deploying correctly or put the SRS into fail-safe mode. Common causes include damaged wiring under the rear seat or water/corrosion in the airbag connector. 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
  • 1Mechanical damage to the wiring harness under the seat: The right rear seat fore-and-aft adjustment mechanism interferes with the wiring harness mounting point. Prolonged chafing damages the insulation, exposing the power wire and causing a short circuit to the vehicle body metal.
  • 2Connector water ingress and corrosion: Driving through water, a blocked sunroof drain tube, or spilled drinks in the rear cause a short circuit between the terminals of the airbag wiring harness connector at the C-pillar or under the seat (usually at the junction of the floor and seat wiring harnesses).
  • 3Airbag module internal fault: High-temperature aging or manufacturing defects damage the inflator igniter coil insulation, causing a short circuit between the two terminals or to the housing.
  • 4SRS ECU drive circuit fault: MOSFET breakdown in the airbag control unit internal boost circuit causes continuous high voltage output at the ignition pin.
  • 5Improper modification or repair: When adding seat ventilation/heating, replacing seat leather, or removing the C-pillar trim panel, retaining clips pierce the wiring harness, or the wiring harness lacks securement along the standard routing.
What To Do
  • 1
    Safe power-down: Turn off the ignition switch, disconnect the 12V battery negative terminal, and wait at least 90 seconds (120 seconds for some models) to fully discharge the SRS backup capacitor and prevent accidental airbag deployment.
  • 2
    Fault confirmation and freeze frame analysis: Use the BYD VDS diagnostic tool to read the complete fault codes and freeze frame data. Record parameters such as vehicle speed, temperature, and voltage at the time of the fault to confirm whether the fault is intermittent.
  • 3
    Visual inspection: Remove the right rear seat (cushion and backrest), lower C-pillar trim panel, and door sill trim panel. Inspect the wiring harness corrugated conduit for damage. Check the connectors (usually marked as GJK series or airbag-specific yellow plugs) for water ingress, corrosion, or backed-out terminals.
  • 4
    Circuit insulation test: Disconnect the airbag module connector (use a shorting bar to short the wiring harness side for safety). Use a multimeter to measure the resistance between the wiring harness side and the positive power supply (B+). Normal resistance is >1MΩ. If continuity exists, strip back the wiring harness in sections to locate the short circuit.
  • 5
    Airbag module resistance measurement: Measure the resistance between the airbag module terminals. Standard value: 1.5-3.0Ω (varies slightly by model). If the resistance is close to 0Ω or infinite, replace the airbag module.
  • 6
    ECU output verification: Connect the diagnostic tool, enter the SRS system, perform an active test (output control), measure the voltage waveform at the ECU output terminal, and check for an abnormal continuous high level.
  • 7
    Repair and reassembly: Repair the damaged wiring harness (use heat shrink tubing or replace the entire harness). Maintain a clearance of at least 20 mm between the wiring harness and the seat slide rail. Use dedicated retaining clips to prevent interference. Apply insulating silicone grease to the connector.
  • 8
    System verification: Restore all connections, connect the battery, and clear the fault codes. Turn the ignition switch to the ON position and verify the SRS warning lamp turns off after the self-check. Perform a simulated crash test (use the diagnostic tool to perform the crash sensor test, not an actual impact) to confirm system function is restored.
Real-World Cases
BYD DTC AI Analysis

Haval H9 front left-centre radar sensor short to power (B190212)

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Symptoms: Continuous alarm when radar system activated, dashboard displayed radar fault, DTC B190212 (front left-centre sensor short to power). Diagnosis: Confirmed DTC present after ignition on; removed front left-centre radar sensor and checked surface for damage (none found); measured supply voltage at ECU (12V, normal); checked sensor power pin connections (secure); substituted known-good sensor into faulty vehicle and DTC cleared, confirming internal short in original sensor. Solution: Replaced front left-centre radar sensor, reactivated radar system, cleared DTCs and tested OK.
Original source ↗
BYD DTC AI Analysis

BYD Song DM intermittent stalling while driving (CAN network communication fault)

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Symptoms: Vehicle occasionally stalls while driving, restarts normally. Irregular fault frequency, no specific warning light on instrument panel. Diagnosis: Diagnostic scan found VCU not communicating. Checked VCU power and ground circuits — supply fuse F4/9 normal. Measured CAN bus voltage and resistance; found backed-out terminal pin at pins G09-14/15 of GJK14 harness connector, causing CAN-H and CAN-L communication interruption. Backed-out pin caused by loose harness retaining clip allowing long-term vibration to pull on connector. Repair: Repaired backed-out CAN harness terminal, re-crimped and secured harness retaining clip, restoring normal VCU communication.
Original source ↗
BYD DTC AI Analysis

BYD Song DM: Abnormal noise from left B-pillar area (body panel welding defect)

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Symptoms: Metallic squeaking from the left B-pillar area while driving, prominent on bumpy roads, unrelated to vehicle speed. Diagnosis: Opened the left front and rear doors and test drove—the noise persisted, ruling out door hinge and check strap faults. Removed the left B-pillar lower trim panel and seatbelt mounting bolts; noise remained. Removed the driver’s seat; same result. Used a stethoscope to isolate the noise to the lower rear of the B-pillar (three-layer steel plate weld joint). No visible weld cracks, but lightly prying the outer steel plate with a tool produced a friction sound. Confirmed: weld separation between the three layers causing microscopic movement and friction. Solution: Cut sections of red plastic tubing (wear-resistant hose) into pads and inserted them between the three B-pillar steel plates as buffers, eliminating direct metal-to-metal contact. Test drive confirmed the fix.
Original source ↗
BYD DTC AI Analysis

BYD Qin Pro right rear airbag wiring harness rubbing against seat rail, causing short circuit

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Symptoms: Airbag warning light intermittently illuminated on rough roads and went out after restart. Scanner showed stored DTC B175212. Diagnosis: Removed right rear seat assembly. Found the under-seat wiring harness retaining clip had detached, leaving the harness hanging above the seat rail. Seat movement caused the rail’s sharp edge to chafe through the harness insulation, shorting the airbag igniter wire (normally routed with power cables in the floor harness) to the body. Measured 0.3Ω to ground. Resolution: Replaced damaged floor harness (or repaired locally), rerouted wiring, and secured it above the seat crossmember with cable ties to keep at least 25mm clearance from the rail. Cleared DTC and drove 50km continuous road test with no recurrence.
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.