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B1761

DTC B1761 indicates the Left Front Side Curtain Airbag ignition drive circuit shorted to the vehicle power supply positive (B+) — Atto 3

Safety System

DTC B1761 indicates the Left Front Side Curtain Airbag ignition drive circuit shorted to the vehicle power supply positive (B+).

In the SRS system, normal airbag igniter resistance is approximately 2.0-3.0Ω.

The control module determines circuit condition by monitoring voltage and resistance.

If wiring harness insulation damage, misaligned connector terminals, or an internal airbag module fault causes the ignition circuit to contact a power wire, the control module detects an abnormally high voltage (near battery voltage).

The module immediately sets DTC B1761 and enters fail-safe mode.

This disables the Left Front Side Curtain Airbag and potentially related airbag functions, preventing deployment during a side impact and creating a severe safety hazard.

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Cases Logged
Real-World Cases
BYD DTC AI Analysis

Song MAX B1761 Fault After Water Wading — A-Pillar Connector Water Ingress Corrosion

✓
A 2019 Song MAX developed a constant airbag warning light after driving through heavy flood water. Scanning revealed DTC B1761. Inspection showed the water level had exceeded the door sills. Removing the A-pillar trim revealed significant water ingress and verdigris inside the left front side curtain airbag connector D111. The technician cleaned the connector terminals, applied conductive grease, and verified normal insulation resistance. They replaced the waterproof seal, re-secured the wiring harness, and cleared the fault. The connector seal had aged and failed during wading, causing a short circuit between terminals.
BYD DTC AI Analysis

Intermittent B1761 fault following Qin Pro accident repair — crushed wiring harness

✓
2020 Qin Pro intermittently set DTC B1761 after side impact collision repairs. Inspection found accident repairs had pinched the left front side curtain airbag wiring harness at the B-pillar trim clip, damaging the insulation and exposing copper wires. Harness movement while driving occasionally contacted body power lines, causing a short. Rerouted the harness to avoid the interference point, wrapped it with fleece tape, secured it, and replaced the damaged section. Fault completely resolved.
BYD DTC AI Analysis

Song Plus B1761 after panoramic sunroof modification — wiring harness pierced by screw

✓
A Song PLUS DM-i showed an airbag warning light after a third-party panoramic sunroof install, with the scanner reading B1761. Inspection revealed that during the modification, the installer missed the wiring clearance when tightening roof crossbeam screws, and a screw pierced the left front side curtain airbag harness, shorting the power wire to the igniter wire. The short was inside the roof rail, so the shop removed the headliner to repair the harness. They replaced the damaged section and adjusted the screw length, clearing the fault. When modifying, strictly follow the body wiring layout diagram.
BYD DTC AI Analysis

Long-term vibration caused B1761 in Qin EV — wiring harness chafing, short to power

✓
A 2020 Qin EV with 120,000 km set a B1761 DTC. Inspection revealed the left front side curtain airbag harness at the A-pillar hinge had suffered insulation damage from vibration due to repeated door opening and closing, with the wiring rubbing against sharp sheet metal edges. Internal conductors contacted both the A-pillar reinforcement beam (ground) and the adjacent interior light power wire simultaneously, creating a short to power. Repaired the damaged harness, fitted rubber protective sleeving and harness retaining clips, and eliminated the vibration source to resolve the fault.
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.