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B175E

DTC B175E indicates the Left Front Side Curtain Airbag ignition circuit resistance is below the normal threshold established by the SRS control unit (ACU) (typically 1 — Atto 3

Safety System

DTC B175E indicates the Left Front Side Curtain Airbag ignition circuit resistance is below the normal threshold established by the SRS control unit (ACU) (typically 1.0–3.0 Ω, depending on model year).

Low resistance indicates a short circuit, either complete (near 0 Ω) or partial.

This fault causes the SRS system to flag the circuit as abnormal.

During a collision, the airbag may fail to deploy or may deploy unintentionally.

Consequently, the ACU illuminates the airbag warning light, stores the fault code, and may disable the entire airbag system to protect occupants.

4
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Song MAX side curtain airbag shorted after water wading

✓
2019 BYD Song MAX, 30,000 km. After wading through heavy floodwater, the airbag warning light stayed on constantly. Read DTC B175E (left front side curtain airbag resistance too low). Live data showed 0.3Ω. Removed the trim below the left A-pillar and found visible water inside the airbag connector. Terminal oxidation caused a short. Cleaned the terminals with electronic contact cleaner, dried them, and applied conductive grease. Resistance returned to normal at 2.2Ω and the fault cleared. Check the door seals and A-pillar waterproof membrane.
BYD DTC AI Analysis

Modified wiring harness crushed on Qin Pro, causing short circuit

✓
2020 BYD Qin (petrol variant). DTC B175E set one week after installing an aftermarket panoramic sunroof ambient lighting kit. Removed the headliner and found the aftermarket wiring harness retaining clips were too long, pinching the left front side curtain airbag harness and damaging the insulation. The exposed copper core shorted to ground against the body. Repaired the harness with insulating tape and heat-shrink tubing, rerouted it to avoid sharp components. Cleared the DTC; it has not returned. Note: Avoid OEM airbag wiring channels when modifying.
BYD DTC AI Analysis

Side curtain airbag inflator internal fault

✓
2019 Song MAX, no collision history. Parked overnight; airbag warning light illuminated on startup. Scanner showed DTC B175E. Disconnected the airbag connector: wiring harness side measured infinite resistance (normal), airbag side measured 0.1Ω (internal short). Replaced the left front side curtain airbag assembly (including gas generator). Fault cleared. Root cause: gas generator internal bridge wire insulation breakdown from aging—component quality defect. Recommend warranty claim.
BYD DTC AI Analysis

A-pillar wiring harness chafed, causing intermittent short circuit

✓
2019 BYD Song MAX. Airbag warning light occasionally illuminated while driving and cleared on restart. DTC B175E (intermittent). Removed left A-pillar trim and inspected the harness; found insulation chafed through at the mounting clip due to repeated door opening and closing. The harness compressed against the clip when the door closed, causing intermittent shorts. Static resistance was normal but dropped below 0.5Ω when wiggling the harness. Replaced the damaged section, added an abrasion-resistant sleeve, and rerouted the harness with adequate slack. Fault completely resolved.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For 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.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.
Data confidence: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.