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B1742-00

DTC B1742-00 indicates the SRS (airbag) control module detects an abnormally low-resistance short circuit between the Left Rear Side Airbag squib circuit and the vehicle positive power supply (+B, typically 12V battery voltage) — Atto 3

Safety System

DTC B1742-00 indicates the SRS (airbag) control module detects an abnormally low-resistance short circuit between the Left Rear Side Airbag squib circuit and the vehicle positive power supply (+B, typically 12V battery voltage).

Under normal conditions, high resistance isolates the airbag squib circuit from both power and ground.

The SRS module internal capacitor releases current only at the moment of deployment.

A short to power causes: 1) airbag deployment failure (the power supply bypasses the trigger current); 2) a risk of unintended deployment (if short circuit resistance changes or voltage fluctuates); 3) the SRS system to enter fail-safe mode, disabling all airbag functions.

This fault is a continuous, non-intermittent hard short.

5
Cases Logged
Real-World Cases
BYD DTC AI Analysis

BYD Qin EV - Rear seat runner chafed through wiring harness

✓
The airbag warning light would illuminate intermittently while driving, and always after rear passengers adjusted their seat position. Technicians removed the left rear seat and found interference between the seat runner and the airbag wiring harness mounting point. Repeated forward and rearward adjustment had chafed through the insulation of the yellow airbag wire, and the exposed copper contacted the 12V power supply wire for the seat heating module, causing a short to power. Stripping back the harness revealed three wear points, one of which had fused to the red wire.
Original source ↗
BYD DTC AI Analysis

BYD Qin EV450 - Rear connector corroded due to water wading

✓
After driving through standing water (depth up to the lower door sill), the airbag warning light on the instrument panel remained on. The scan tool retrieved code B1742-00. Inspection found obvious mud and water traces inside the white 2-pin airbag connector under the left rear seat. Electrolytic corrosion between the pins formed green oxide, reducing resistance between the power and signal pins to 0.5Ω and causing a short to power.
Original source ↗
BYD DTC AI Analysis

BYD Qin 100 - Aftermarket seat cover damaged wiring harness

✓
After the owner fitted full-surround genuine leather seat covers, the airbag warning light immediately came on and stayed on. Inspection found that metal staples securing the covers had pierced the left rear side airbag wiring harness sheath, causing a short between the airbag igniter wire (yellow) and the seat heater power wire (red). A multimeter reading showed 0Ω resistance to the power supply terminal. After removing the staples and repairing the harness, the fault cleared.
Original source ↗
BYD DTC AI Analysis

BYD Qin 80 - Connector locking tab broke, causing the plug to come loose and short out.

✓
The vehicle operated as a ride-share car. Rear passengers frequently kicked the left rear C-pillar area. Inspection found the left rear side airbag connector locking tab fractured, so the connector did not fully latch. On bumpy roads the connector shifted, the pins contacted the adjacent 12V constant power terminal and caused an intermittent short to power. Replaced the connector and re-secured the wiring harness routing. Problem resolved.
Original source ↗
BYD DTC AI Analysis

BYD Qin EV300 - Wiring harness retaining clip aged and detached.

✓
The vehicle is 5 years old. The factory wiring harness retaining clip under the left rear seat had aged and snapped, allowing the harness to sag and contact the seat rail. An aftermarket rear seat heater was installed later; its 12V power cable insulation had worn through and bonded to the OEM airbag harness, causing fault B1742-00. Repair involved reorganising both harnesses, replacing the clip, and separating the high- and low-voltage circuits.
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.