AU
B175A

DTC B175A indicates the Right Rear Side Airbag ignition circuit resistance measures 0Ω, indicating a short to ground in the airbag circuit or an internal short circuit in the airbag module — Qin Plus

Safety System

DTC B175A indicates the Right Rear Side Airbag ignition circuit resistance measures 0Ω, indicating a short to ground in the airbag circuit or an internal short circuit in the airbag module.

Normal airbag inflator resistance ranges between 1.5 and 3.5 ohms (typically 2.0-2.8Ω).

When the SRS control module detects a resistance of 0Ω, it identifies a circuit short fault, immediately disables airbag deployment, and illuminates the instrument panel airbag fault warning lamp.

Due to this fault, the Right Rear Side Airbag may fail to inflate and deploy during a side impact, severely compromising occupant protection.

Common causes include wiring harness wear, connector water ingress, or an internal short circuit in the airbag module.

The B175A fault code on the Qin Plus indicates a medium-severity fault in the right rear side airbag ignition circuit, where resistance reads 0Ω due to a short to ground or internal airbag module short. Common causes include chafed SRS wiring under the right rear seat or water ingress/bent pins in the airbag connector. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
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Cases Logged
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Causes
Likely Causes — Qin Plus
  • 1Short to ground caused by chafed SRS wiring harness under the right rear seat: Fore-and-aft sliding or height adjustment causes the yellow SRS wiring harness under the seat to rub against the metal slide rail or spring. Damaged insulation allows the copper wire to directly contact the vehicle body ground.
  • 2Airbag connector water ingress or bent pin short circuit: The right rear side airbag connector is located on the side of the seat backrest or inside the C-pillar trim panel. Water easily enters the connector during vehicle wading, improper car washing, or rainy seasons, causing a short circuit between the pins. Alternatively, disconnecting and reconnecting the connector during seat repairs can bend the pins, causing pin-to-pin contact.
  • 3Airbag module (gas generator) internal short circuit: An internal short circuit in the airbag igniter bridge wire or damp propellant causes an abnormal resistance drop. This condition is rare but requires replacing the entire airbag module.
  • 4SRS control module internal detection circuit fault: A damaged resistance detection circuit inside the control module triggers a false short-circuit fault; the actual wiring and airbag are normal.
  • 5Wiring harness incorrectly secured after seat removal and installation: After repairing the seat leather or heating pad, failing to properly clip the SRS wiring harness into the retaining slot allows the seat frame to pinch the harness, causing a short circuit.
What To Do
  • 1
    Safety preparation and fault confirmation: Disconnect the negative battery terminal and wait at least 3 minutes. Use the BYD dedicated diagnostic tool VDS or Launch X431 to confirm DTC B175A. Check the resistance value in the freeze frame data (should display 0.0 Ω). Check for accompanying SRS fault codes (such as B175B left rear side airbag fault).
  • 2
    Visually inspect the connector: Remove the right rear seat backrest side trim panel or lower C-pillar trim panel. Locate the yellow SRS wiring harness connector (usually with a double-locking mechanism). Inspect the inside of the connector for water stains, oxidation, corrosion, or bent or deformed pins. Clean with electrical contact cleaner and blow dry.
  • 3
    Harness continuity test: Disconnect the airbag connector. Use a multimeter to measure the resistance between the harness side (body side) and body ground. A normal reading displays infinity (OL). A reading of 0 Ω or close to 0 Ω indicates a short to ground in the harness; continue troubleshooting.
  • 4
    Detailed under-seat wiring harness inspection: Remove the right rear seat assembly and fully open the under-seat wiring harness sleeve. Inspect the contact points between the wiring harness and the seat slide rails, springs, and metal brackets for insulation wear, cuts, or indentations. Repair any damage using heat-shrink tubing and waterproof tape. Reroute the wiring harness and secure it with cable ties to prevent interference with moving parts.
  • 5
    Airbag module resistance measurement: Use a dedicated airbag resistance measuring tool (or high-impedance multimeter) to measure the resistance of the airbag assembly (gas generator). The normal range is 1.5-3.5 Ω. If the reading is 0 Ω or near 0 Ω, the airbag module has an internal short circuit. Replace the right rear side airbag module. (Note: Disconnect power from the airbag before measurement and use the dedicated resistance measurement mode to prevent accidental deployment.)
  • 6
    SRS control module verification: If the wiring harness and airbag module are normal, suspect an SRS control module fault. Inspect the control module connector (usually located under the center console or behind the center armrest) for looseness. Use an oscilloscope to check the diagnostic signal waveform output by the control module. If necessary, replace and recode the SRS control module.
  • 7
    System reset and verification: After completing repairs, reconnect all connectors (listen for the locking click), connect the battery, and clear the fault codes. Turn the ignition switch to the ON position and observe the instrument panel airbag warning light: it should turn off after 6 seconds. Use a diagnostic tool to read the data stream and confirm the right rear side airbag resistance displays within the normal range (1.5-3.5Ω). Finally, perform a seat fore-and-aft sliding test to verify the wiring harness does not interfere.
Real-World Cases
BYD DTC AI Analysis

Worn right rear seat wiring harness caused B175A in BYD Tang DM

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Vehicle: 2021 Tang DM. Symptom: Instrument panel airbag warning light stayed on constantly. Read DTC B175A (right rear side airbag resistance: 0Ω). Diagnosis: Removed the right rear seat and found the yellow SRS wiring harness sheath underneath had been cut by the seat slide rail edge, with two internal wires exposed and touching the metal rail to create a short to ground. This line supplies the right rear side airbag. Repair: Cut out the damaged harness section, re-soldered the wires and insulated them with heat-shrink tubing. Rerouted the harness, added protective sleeving and securing clips at wear-prone points, and ensured the harness maintains at least 10mm clearance from the rail. After clearing the DTC, the airbag light went out and the data stream showed resistance had returned to 2.3Ω.
Original source ↗
BYD DTC AI Analysis

BYD Song MAX B175A Fault Code Repair After Water Ingress

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Vehicle: 2019 BYD Song MAX. Symptom: After driving through water, the instrument cluster displayed an airbag fault. The scanner read DTC B175A (right rear side airbag short circuit). Diagnosis: Inspected the airbag connector behind the right rear C-pillar trim and found obvious water staining and green corrosion inside, with a micro-short between pins caused by electrolytic corrosion. The C-pillar seal had degraded, letting water soak the connector during the water crossing. Repair: Cleaned the connector pins with electrical contact cleaner and fine sandpaper, dried them with compressed air, and applied contact protectant. Replaced the C-pillar seal to prevent recurrence. The airbag module was undamaged; cleaning the connector fixed the fault and restored normal resistance.
Original source ↗
BYD DTC AI Analysis

B175A false positive after seat removal and refitting on BYD Qin Pro

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Vehicle: 2020 BYD Qin Pro. Symptom: DTC B175A appeared after replacing the right rear seat leather cover. Diagnosis: Inspected the wiring harness beneath the seat. The SRS harness was not clipped into its retaining slot; the seat frame pinched it instead. This compressed and deformed the insulation without breaking it, causing resistance to drop to 0Ω at specific seat positions. Repair: Rerouted the harness, reinforced the insulation with specialized harness tape, and clipped the SRS harness into the factory retaining clip to ensure adequate clearance from the seat frame. Cleared the DTC and tested by repeatedly adjusting the seat position; the fault did not recur.
Original source ↗
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.