UAE
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B175B1A

DTC B175B1A indicates the right rear side airbag igniter circuit resistance falls below the normal ECU threshold (typically below 1 — Atto 3

Safety System

DTC B175B1A indicates the right rear side airbag igniter circuit resistance falls below the normal ECU threshold (typically below 1.0 Ω).

In the BYD SRS (Supplemental Restraint System), standard airbag igniter resistance is generally 2.0–3.0 Ω.

If the ECU continuously detects abnormally low circuit resistance, it logs a short circuit fault (indicating a possible short to ground or internal igniter short circuit).

This fault causes the following: 1) The airbag may fail to deploy during a collision, resulting in a loss of side protection. 2) The airbag may deploy unexpectedly in extreme cases. 3) The SRS enters fail-safe mode and illuminates the airbag warning light.

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

2
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Steering wheel cruise control switch failure (B17 series reference)

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Symptoms: Steering wheel cruise control switch completely inoperative. Pressing the 'Set' button gets no response, and the instrument cluster shows no cruise setting information. Some owners reported abnormal instrument cluster warnings. Diagnosis: The owner replaced the steering wheel cruise control switch assembly, instrument panel relay assembly, and instrument cluster assembly one by one, but the fault remained. Technicians suspected either a faulty Set button or an internal break in the steering wheel clock spring wiring, blocking the switch signal from reaching the BCM. Solution: The forum post did not record a final confirmed solution. Follow-up posts suggested checking the steering wheel clock spring ribbon cable, multifunction switch connectors, and Body Control Module (BCM) software version. Note: Although this is not a direct B175B1A case, it demonstrates the wiring troubleshooting approach for B17-series fault codes.
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BYD DTC AI Analysis

VCU communication interrupted (pin backed out)

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**Symptoms:** Scan tool cannot communicate with the Vehicle Control Unit (VBU/VCU). Some electronic functions failed and the instrument cluster may display "Check Power System" or related warning lights. **Diagnosis:** Technician checked power, ground and CAN bus communication. Found pins G09-14/15 (GJK14 harness junction) backed out, breaking the communication signal. Confirmed fuse F4/9 had not blown, ruling out power supply problems. **Repair:** Fixed the backed-out pins in the wiring harness connector and re-secured the terminals for proper contact. Cleared DTCs with the scan tool. VCU communication returned to normal. **Note:** This case shows a system failure caused by wiring harness connector pin retraction in BYD vehicles. Useful reference for troubleshooting poor harness connections in SRS systems.
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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.