AU
B1768

DTC B1768 on models such as the 2019 BYD Song MAX and 2020 Qin ICE indicates a short to ground in the right front side curtain airbag ignition circuit — Atto 3

Safety System

DTC B1768 on models such as the 2019 BYD Song MAX and 2020 Qin ICE indicates a short to ground in the right front side curtain airbag ignition circuit.

The SRS ECU detects abnormally low resistance in the airbag inflator circuit (usually <2Ω), indicating damaged wiring insulation causing a short to body ground, or an internal short circuit in the airbag module.

This fault prevents the affected airbag from deploying during a collision (fail-safe state) or, in very rare cases, creates a risk of unintended deployment due to circuit interference.

This constitutes a highest-level safety fault.

Note: Other BYD models (such as the Song Pro, Qin PLUS, and Han EV) may define B1768 as an abnormal left front door lock status signal.

Verify the specific vehicle model and year.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Right front side curtain airbag wiring harness chafed or crushed inside the A-pillar/B-pillar trim panel, causing the wire to short to the vehicle body metal.
  • 2Water ingress, oxidation, or bent pins at the airbag connector (usually located near the right roof grab handle or C-pillar) causing a short to ground.
  • 3Airbag module internal igniter resistance wire short circuit (internal fault); resistance measures close to 0 Ω.
  • 4After a vehicle accident, unrepaired metal burrs cut the airbag wiring harness, or failure to correctly wrap the harness during repair.
  • 5SRS ECU internal monitoring circuit fault causing a false short circuit (less common; confirm after ruling out wiring issues)
What To Do
  • 1
    Safety preparation: Power down the vehicle, disconnect the battery negative terminal, and wait at least 90 seconds to discharge the SRS capacitors completely and prevent accidental airbag deployment.
  • 2
    Fault confirmation: Use VDS or a dedicated diagnostic tool to read the fault code. Confirm B1768 is a current fault (Active) and record the freeze frame data.
  • 3
    Visual inspection: Remove the right A-pillar, B-pillar, and headliner edge trim panels. Inspect the right front side curtain airbag wiring harness (usually wrapped in yellow corrugated conduit) for obvious wear, cuts, or crush marks.
  • 4
    Connector check: Disconnect the connector between the airbag module and the main wiring harness (a shorting bar usually protects this connection). Inspect the pins for oxidation, water ingress, or deformation. Measure the resistance to ground on the harness side of the connector; the value must be infinite.
  • 5
    Resistance measurement: Use a multimeter to measure the igniter resistance on the airbag module side. The standard value is 2.0Ω-3.0Ω. If the reading is close to 0Ω, the module has an internal short circuit. Replace the module.
  • 6
    Wiring repair: If the wiring harness is damaged, use dedicated heat-shrink tubing or replace the wiring harness. Maintain clearance from the vehicle body and secure the harness firmly to prevent further chafing.
  • 7
    System reset: After repair, reconnect all connectors, reinstall the trim panels, and connect the battery. Use the diagnostic tool to clear the fault code and perform an SRS system self-check. Verify B1768 does not return and the airbag warning light turns off normally.
Real-World Cases
BYD DTC AI Analysis

Worn right A-pillar wiring harness caused B1768 in Song MAX

✓
Symptoms: Airbag warning light on. Scanner read B1768 (right front side curtain airbag short to ground). Diagnosis: Removed the A-pillar trim and found the right front airbag wiring harness chafing against the clip. Friction wore through the insulation, exposing the copper wire to the chassis metal. Repair: Repaired the damaged wiring, rerouted the harness to avoid the sharp clip, and replaced the airbag connector. Fault cleared.
Original source ↗
BYD DTC AI Analysis

BYD Qin petrol version airbag connector water ingress, oxidation and short circuit

✓
Symptoms: Airbag warning light illuminated after driving in rain. DTC B1768. Diagnosis: Water entered the right front side airbag connector at the C-pillar due to a deteriorated rear window seal, causing pin oxidation and a short to ground. Repair: Cleaned and blow-dried the connector, applied dielectric grease, and replaced the rear window seal. Fault cleared.
Original source ↗
BYD DTC AI Analysis

After accident repair, unaddressed wiring harness burrs caused intermittent B1768

✓
Symptoms: Intermittent B1768 DTC after right front collision repairs. Diagnosis: The accident deformed the right side body structure. Metal burrs created during panel beating repairs pierced the SRS wiring loom insulation, causing intermittent shorts to ground over bumps. Repair: Ground down the burrs and replaced the damaged loom section. Fault fully resolved.
Original source ↗
BYD DTC AI Analysis

Internal short circuit in right front side curtain airbag module

✓
Symptom: Airbag warning light stays on; DTC B1768 cannot clear. Diagnosis: Disconnected the airbag module connector and measured 0.3Ω at the module side (normal: 2–3Ω). Determined internal short in the airbag igniter. Repair: Replaced the right front side curtain airbag module, reconfigured the SRS system, and cleared the fault code.
Original source ↗
BYD DTC AI Analysis

Loose connection at SRS ECU connector causing false B1768

✓
Symptoms: Airbag warning light illuminates intermittently when driving on bumpy roads, storing DTC B1768. Diagnosis: Inspected wiring—no damage found. Resistance measurements normal. SRS ECU connector pin partially backed out, causing abnormal monitoring voltage and false short-circuit detection. Repair: Reseated ECU connector pin and secured connection. Fault resolved.
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: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.