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B174B1A

This DTC indicates the left rear side airbag squib resistance falls below the normal threshold set by the SRS control module (ACU) (typically below 1 — Atto 3

Safety System

This DTC indicates the left rear side airbag squib resistance falls below the normal threshold set by the SRS control module (ACU) (typically below 1.2Ω-1.5Ω; standard range is generally 1.5Ω-3.5Ω).

Low resistance usually indicates a short circuit in the squib circuit.

Possible causes include a wiring harness short to ground, a wire-to-wire short, an internal connector short, or an internal short within the airbag module itself.

This fault causes the SRS system to classify the airbag as unsafe.

The airbag may fail to deploy during a collision (as the system may disable the circuit to prevent accidental deployment), or it poses a risk of unintended deployment.

This is an active safety system fault requiring immediate repair.

3
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Qin Pro DM: Left rear airbag harness pin backed out, resulting in low resistance

✓
The airbag warning light illuminated intermittently while driving. Read DTC B174B1A. Inspection found pins 14 and 15 of airbag connector G09 beneath the left rear seat had backed out, causing poor contact and intermittent short circuits, resulting in low and unstable resistance readings. Reseated the pins, ensured the connector locks were intact, cleared the DTC, and resolved the fault.
Original source ↗
BYD DTC AI Analysis

Qin Pro seat adjustment chafed the airbag wiring harness, causing a short circuit.

✓
Owner reported the airbag warning light came on after adjusting the left rear seat position. Diagnosis found the wiring harness interfering with the seat rail. Long-term friction wore through the insulation, causing a short to ground with low resistance (measured 0.8Ω). Repaired the harness, rerouted the wiring, and added harness clips to keep it clear of the seat mechanism. Fault resolved.
Original source ↗
BYD DTC AI Analysis

False internal fault report in Qin Pro SRS control module

✓
Vehicle had no collision history but logged frequent B174B1A faults. Measured airbag and harness resistance at 2.1 Ω (normal). Diagnosed an internal sampling circuit fault in the SRS ECU causing false low-resistance readings. Replaced the airbag control module (ACU), recoded and calibrated the seat occupancy sensor. Fault has not returned.
Original source ↗
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.