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 — Atto 8

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 Atto 8 indicates a short circuit in the right rear side airbag igniter circuit, with resistance reading 0 ohms instead of the normal 2.0–3.0 ohms. This is a medium-severity SRS fault that may stop the airbag from deploying and keep the warning light on. Common causes include a faulty airbag igniter or damaged wiring. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Airbag igniter internal short circuit: Moisture, manufacturing defects, or aging causes an internal short circuit in the igniter bridgewire or pyrotechnic charge inside the airbag module.
  • 2Wiring harness short circuit: Seat adjustment wear, pinching, 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: Airbag connector (usually yellow) has bent or backed-out terminals, or the shorting bar did not separate correctly during mating, causing a short circuit between terminals.
  • 4Internal control module fault: Damaged airbag drive circuit inside the SRS ECU falsely reports a low-resistance fault.
  • 5Improper repair operations: Connecting or disconnecting the airbag connector without disconnecting the battery during recent removal or installation of the seat or interior trim panel, causing static discharge or an accidental short in the trigger circuit.
What To Do
  • 1
    Safety preparation: Turn the vehicle 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 (Qin series models typically mount this on the side of the right rear seat backrest or inside the lower C-pillar 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 a dedicated shorting clip to prevent static electricity). Measure the resistance between the terminals on the airbag assembly side connector using a digital multimeter. Standard value: 2.0-3.0 Ω. If the resistance is 0 Ω, replace the airbag assembly.
  • 4
    Harness inspection: Measure resistance to ground at the harness-side connector terminals and resistance between terminals. If resistance is 0 Ω or extremely low, inspect the entire harness (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 DTC. If the fault disappears, the original airbag assembly is faulty. If the fault persists, 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 lamp 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

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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

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**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

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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.

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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 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.