AU
B175A-00

DTC B175A-00 indicates the Airbag Control Module (ACM) detects 0 ohms resistance in the igniter (inflator) circuit of the right rear side airbag, typically located in the right rear seat side or C-pillar trim panel — Qin Plus

Safety System

DTC B175A-00 indicates the Airbag Control Module (ACM) detects 0 ohms resistance in the igniter (inflator) circuit of the right rear side airbag, typically located in the right rear seat side or C-pillar trim panel.

Normal igniter resistance is 2.0-3.0 ohms.

A resistance of 0 indicates a short circuit.

Possible causes include an internal igniter short, a wiring harness short to ground, a short between connector terminals, or a control module internal driver circuit fault.

This fault forces the SRS system into fail-safe mode.

The right rear side airbag may fail to deploy during a collision, and the airbag warning lamp (SRS lamp) may illuminate continuously.

The B175A-00 fault code on the Qin Plus indicates a short circuit in the right rear side airbag igniter circuit, with resistance detected at 0 ohms instead of the normal 2.0-3.0 ohms. Severity is medium because the SRS may enter fail-safe mode and the airbag may not deploy. Common causes include a shorted airbag igniter or damaged wiring under the seat/C-pillar. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Airbag igniter internal short circuit: Moisture, manufacturing defects, or aging causes an internal short circuit in the igniter bridge wire or pyrotechnic charge inside the airbag module.
  • 2Wiring harness short circuit: Seat adjustment wear, crushing, water ingress, or rodent chewing damaged the wiring harness insulation under the right rear seat or in the C-pillar area, causing a short to ground or a short between twisted pair wires.
  • 3Connector fault: Bent or backed-out terminals in the airbag connector (usually yellow), or the shorting bar failed to separate correctly during connection, causing a short circuit between terminals.
  • 4Internal control module fault: Damaged airbag drive circuit inside the SRS ECU causes a false low-resistance fault.
  • 5Improper repair operations: Connecting or disconnecting the airbag connector without disconnecting the battery during recent seat or interior trim removal or installation, causing static electricity or an accidental short circuit in the trigger circuit.
What To Do
  • 1
    Safety preparation: Set the vehicle to OFF, disconnect the 12V battery negative terminal, and wait at least 90 seconds to fully discharge the SRS capacitor and prevent accidental airbag deployment.
  • 2
    Locate the component: Confirm the position of the right rear side airbag (on Qin series models, usually located on the side of the right rear seat backrest or inside the C-pillar lower trim panel). Visually inspect the yellow dedicated connector and wiring harness for damage, water stains, or crush marks.
  • 3
    Isolation measurement: Disconnect the airbag connector (use the dedicated shorting clip to prevent static electricity). Use a digital multimeter to measure the resistance between the terminals on the airbag module side connector. Normal value: 2.0-3.0Ω. If 0Ω, replace the airbag module.
  • 4
    Harness inspection: Measure resistance to ground and resistance between terminals at the harness-side connector. If resistance is 0Ω or extremely low, inspect the entire harness routing (especially at seat slide rails and hinges). Repair damaged insulation or replace the harness.
  • 5
    Simulation test: Connect a 2.7Ω dedicated simulation resistor (substitute load) to the SRS ECU-side wiring harness. Clear the fault code. If the fault disappears, the original airbag assembly is faulty. If the fault remains, check the SRS ECU or wiring harness for a short to ground.
  • 6
    System reset: After repair, reconnect all connectors (listen for the locking click) and connect the battery. Use the VDS diagnostic tool to clear the fault code and perform the 'SRS system self-learning/configuration' procedure. Confirm B175A-00 does not return and the SRS warning light turns off normally.
Real-World Cases
BYD DTC AI Analysis

Song Pro DM left-hand temperature blend door actuator internal motor open circuit

✓
Symptoms: At 32,000 km, left vent blows hot air with AC on regardless of temperature setting (16°C or 28°C). Right side normal; no warning lights. Diagnosis: VDS showed AC DTC B175A-00 (driver side temperature blend door actuator fault). Disassembly revealed actuator motor resistance infinite (normal 20-50Ω) and internal plastic gear stripped. Repair: Replaced left side temperature blend door actuator assembly (HAC-8107310) and ran blend door initialization.
Original source ↗
BYD DTC AI Analysis

Qin Plus EV temperature blend door actuator binding caused by installation stress

✓
Symptoms: 6-month-old vehicle. Left side of dual-zone climate control has delayed temperature regulation (5-minute cooling-to-heating transition) with clicking noise. Diagnosis: History DTC B175A-00 stored in HVAC system. Disassembly found actuator mounting bracket assembly stress caused misalignment between the output shaft and damper linkage, making the position sensor voltage jump between 0.5V–2.3V instead of sweeping smoothly from 0.5V–4.5V. Repair: Re-adjusted actuator mounting angle to eliminate stress and applied low-temp grease to the linkage.
Original source ↗
BYD DTC AI Analysis

Deformed HVAC housing after accident repairs caused Tang DM-i actuator disconnection

✓
**Symptoms:** Minor right-front impact at 15 km/h. After replacing the front bumper and right fender, the left side blew only cold air — no heat. **Diagnosis:** The collision didn’t touch the AC system, but current DTC B175A-00 was stored. Inspection revealed slight deformation of the HVAC housing: the left temperature blend door actuator mounting bracket had shifted, the output shaft detached from the blend door, and the actuator spun freely. **Resolution:** Adjusted the HVAC housing mounting position, reconnected the actuator to the blend door, manually calibrated the blend door zero position, and ran the AC self-learning procedure.
Original source ↗
BYD DTC AI Analysis

Han EV wiring harness connector oxidation caused intermittent temperature control failure

✓
Symptoms: Intermittent left-side temperature control failure; system recovers after restart. Occurs every 1–2 weeks with panel flickering. Diagnosis: Intermittent history DTC B175A-00. Found green corrosion on B09 connector pins under left dashboard. Actuator supply voltage drops to 9V during fault (normal 12V). Repair: Cleaned B09 connector pins with contact cleaner and conductive protective grease. Added wiring harness retaining clips to prevent vibration.
Original source ↗
BYD DTC AI Analysis

Aftermarket center screen installation on Song Max caused loose connection at actuator connector.

✓
Symptoms: One week after installing an aftermarket centre display, the left-side AC temperature stuck at maximum heat and would not adjust. Fuel consumption increased. Diagnosis: DTC B175A-00. Inspection found the left-side temperature blend door actuator connector loose from dashboard disassembly during the modification. The aftermarket head unit also had a CAN protocol conflict, sending incorrect blend door position commands that stalled the actuator. Repair: Reseated the actuator connector and wrapped it with waterproof tape. Disconnected the aftermarket head unit from the CAN bus, retaining only power and audio/video connections.
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.