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 8

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 8
  • 1Wear or crushing inside the A-pillar/B-pillar trim damages the right front curtain airbag wiring harness, causing the wire to short to the vehicle body metal.
  • 2Airbag connector (usually located near the right roof grab handle or C-pillar) shorted to ground due to water ingress, oxidation, or bent pins.
  • 3Airbag module internal igniter resistance wire short circuit (internal fault); resistance measures close to 0 Ω.
  • 4After an accident, unrepaired metal burrs cut the airbag wiring harness, or the harness was incorrectly wrapped during repair.
  • 5SRS ECU internal monitoring circuit fault causing a false short circuit report (uncommon; rule out wiring faults before confirming)
What To Do
  • 1
    Safety preparation: Power down the vehicle, disconnect the battery negative terminal, and wait at least 90 seconds to fully discharge the SRS capacitors and prevent accidental airbag deployment.
  • 2
    Fault Confirmation: Use VDS or a dedicated diagnostic tool to read fault codes, confirm B1768 is a current fault (Active), and record freeze frame data.
  • 3
    Visual inspection: Remove the right A-pillar, B-pillar, and headliner edge trims. Check the right front curtain airbag wiring harness (usually wrapped in yellow corrugated conduit) for obvious wear, cuts, or crush marks.
  • 4
    Connector inspection: Disconnect the connector between the airbag module and the main wiring harness (usually protected by a shorting bar). Inspect the pins for oxidation, water ingress, or deformation. Measure the resistance to ground on the harness side of the connector; the resistance 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. Keep the harness clear of the vehicle body and fasten it securely to prevent recurring wear.
  • 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-test. Verify DTC B1768 does not return and the airbag warning light turns off.
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 8 Fault Codes
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.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 overview →
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.