AU
B1767

DTC B1767 indicates an abnormally low-resistance connection between the right front side curtain airbag inflator circuit and the vehicle positive power supply terminal (B+), resulting in a short to power — Atto 8

Safety System

DTC B1767 indicates an abnormally low-resistance connection between the right front side curtain airbag inflator circuit and the vehicle positive power supply terminal (B+), resulting in a short to power.

Under normal conditions, the airbag inflator circuit maintains high impedance (open-circuit state, with resistance typically between 2-5Ω) and conducts only momentarily when the Airbag Control Unit (ACU) triggers it.

This fault indicates the airbag circuit may remain continuously energized even if the ACU does not issue a deployment command, causing two serious consequences: 1) The airbag may deploy unexpectedly during vehicle operation, causing serious occupant injury. 2) The system detects the abnormal voltage and enters protection mode, disabling the entire SRS system and preventing airbag deployment during a collision.

This hard short-circuit fault typically causes the SRS warning lamp to illuminate continuously.

Clearing the fault code will not resolve the issue.

5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Right front curtain airbag wiring harness insulation worn or broken: Long-term vibration, temperature changes, or interior trim removal and installation damages the wiring harness located inside the headliner trim panel from the right A-pillar to the C-pillar. This shorts the ignition wire (usually the positive trigger wire) to a constant power circuit (such as the reading light or ambient light power wire).
  • 2Water ingress or corrosion in the airbag connector: Water leaks from a blocked sunroof drain hose, car washing, or wading cause a short circuit between terminals in the right front side airbag connector (usually located inside the B-pillar or C-pillar trim). Specifically, electrolytic corrosion creates continuity between the igniter pin and the power supply pin.
  • 3Internal short circuit in the airbag module: Manufacturing defects or moisture ingress cause an internal short circuit in the curtain airbag inflator igniter tube (squib), creating abnormal continuity between the ignition terminals and the module metal housing (ground) or internal power supply circuit.
  • 4Vehicle modifications causing wiring harness damage: when installing a dash cam, roof ambient lighting, roof rack, or replacing the headliner trim, fixing screws or wiring harness clips pierce the SRS wiring harness, or aftermarket wiring incorrectly connects to the airbag circuit.
  • 5SRS control unit (ACU) internal drive circuit fault: A damaged airbag ignition drive chip (such as a MOSFET or ASIC chip) inside the ACU shorts the output terminal to the internal power supply, triggering a false short-to-power fault.
What To Do
  • 1
    Safety Preparation and Fault Confirmation: Shift the vehicle into P or Neutral, apply the parking brake, disconnect the 12V battery negative terminal, and wait at least 90 seconds (to ensure the SRS capacitor fully discharges). Connect the diagnostic tool to confirm B1767 is an active fault, record the freeze frame data, and check for accompanying airbag circuit fault codes.
  • 2
    Visual inspection and wiring harness check: Remove the right A-pillar, B-pillar, and C-pillar interior trim panels. Inspect the right front curtain airbag wiring harness (wrapped in yellow corrugated conduit) for wear, cuts, or burn marks. Focus on contact points between the wiring harness and body metal edges, trim clips, and the sunroof drain hose. Use a multimeter to measure the resistance between the ignition wire and body ground, and between the ignition wire and constant power (normal value: infinite).
  • 3
    Connector inspection: Disconnect the right front side airbag connector (usually located below the B-pillar or above the C-pillar). Check the terminals for oxidation, corrosion, backed-out pins, or foreign matter. Measure the harness-side connector terminal voltage (should be 0V; 12V indicates a short to power in the harness). If necessary, clean the terminals with electrical contact cleaner and apply conductive protectant.
  • 4
    Airbag module check: Connect the dedicated airbag load simulator (SRS Simulator) in place of the airbag module, clear the fault code, and cycle the power. If the fault code disappears, this confirms an internal short circuit in the airbag module. Replace the right front curtain airbag module. If the fault code remains, the fault is in the wiring harness or the ACU.
  • 5
    Wiring harness insulation repair or replacement: If the wiring harness is damaged, wrap the damaged area with high-temperature insulating tape (Kapton tape) and re-secure the harness to prevent interference. If the harness has multiple damaged sections or an internal short circuit, replace the entire right front side airbag wiring harness assembly to prevent recurrence.
  • 6
    SRS control unit diagnosis: Disconnect the ACU connector and measure the resistance between the right front side airbag ignition output terminal and the power supply. If continuity exists, the ACU has an internal fault. Replace the airbag control unit and perform coding configuration.
  • 7
    System reset and verification: After completing repairs, reconnect all connectors (listen for a locking click), connect the battery, and use the diagnostic tool to clear the fault code. Perform an SRS system self-check (normally, after turning the ignition switch ON, the SRS warning lamp illuminates for 6 seconds and then turns off). Use the diagnostic tool to read the data stream and confirm the right front side airbag circuit resistance is within the normal range (1.5-3.5Ω). Perform static and dynamic road tests to verify the repair.
Real-World Cases
BYD DTC AI Analysis

BYD Song MAX right front side airbag short circuit after water wading

✓
A 2019 Song MAX had the SRS warning light stay on constantly after wading through heavy rain. Read DTC B1767. Inspection revealed standing water in the right C-pillar airbag connector with oxidised, blackened terminals. The right-side sunroof drain tube had detached, allowing rainwater to run down the A-pillar and into the C-pillar trim. Fix: Cleared water from the connector, cleaned the terminals with electronic cleaner and blew dry, reattached the sunroof drain tube. Fault resolved.
BYD DTC AI Analysis

Aftermarket dash cam installation damaged wiring harness on BYD Qin Pro

✓
While installing a dashcam, the owner of a 2020 Qin Pro drove cable-clip fasteners into the right-hand A-pillar SRS harness, damaging the airbag igniter wire insulation. This caused a short to constant power and set DTC B1767. Disconnecting the airbag module changed the code to open-circuit (high resistance), confirming a wiring fault. Repaired the harness by rewrapping the insulation and rerouted the dashcam wiring to avoid the SRS harness.
BYD DTC AI Analysis

Internal short circuit in Song PLUS airbag module

✓
A Song MAX had the SRS warning light suddenly come on during normal operation. The scanner showed B1767. No wiring harness damage or connector abnormalities found. Substituting an airbag simulator cleared the fault. Confirmed internal short in the right front side curtain airbag gas generator. Repair: Replaced the right front side curtain airbag module (requires headliner removal), then performed SRS system configuration and calibration. Fault resolved.
BYD DTC AI Analysis

BYD Qin DM SRS fault after accident repairs

✓
A Qin petrol model's SRS warning light remained on after right-side collision repairs. DTC B1767. Inspection found the airbag wiring harness had been crushed by right C-pillar trim clips during the repair, deforming it and causing an internal short to the power supply. Replaced the damaged harness section (from ACU to airbag module), rerouted the wiring properly and fitted harness protection sleeving. Fault resolved.
BYD DTC AI Analysis

Internal driver chip in SRS control unit damaged

✓
A 2019 Song MAX exhibited an intermittent SRS warning light during normal operation. Fault codes cleared initially but recurred; eventually B1767 became a permanent fault. Inspection confirmed the wiring harness and airbag module tested normal. Testing revealed continuity between the right front airbag drive terminal inside the ACU and the positive power supply. Resolution: Replaced the airbag control unit (ACU), programmed the VIN and calibrated the crash sensors using a dedicated diagnostic tool. Fault completely resolved.
Other Atto 8 Fault Codes
B1108For 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.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.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
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.