AU
B1763

DTC B1763 indicates the airbag control unit (SRS ECU) detects a 0 Ω (or near 0 Ω) resistance in the right front curtain shield airbag igniter circuit — Seal 6 EV

Safety System

DTC B1763 indicates the airbag control unit (SRS ECU) detects a 0 Ω (or near 0 Ω) resistance in the right front curtain shield airbag igniter circuit.

Normal airbag igniter resistance is 2.0-5.0 Ω.

A 0 Ω resistance indicates a short in the igniter circuit.

Possible causes include an internal igniter short, a wiring harness short to ground (GND) or power (B+), or a faulty SRS ECU internal drive circuit.

This fault causes the SRS system to enter fail-safe mode.

During a collision, the affected curtain shield airbag may fail to deploy.

The instrument panel SRS warning light illuminates continuously to indicate limited occupant protection system functionality.

The B1763 fault code on the Seal 6 EV indicates a short circuit in the right front curtain shield airbag igniter circuit, with resistance near 0 Ω instead of the normal 2.0–5.0 Ω. Severity is medium because the SRS may enter fail-safe mode and the affected curtain airbag may not deploy in a crash. Common causes include a shorted igniter or damaged wiring. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Seal 6 EV
  • 1Internal short circuit in the right front curtain airbag igniter: Manufacturing defects, aging, or prolonged vibration cause the igniter bridge wire inside the airbag module to break and short together.
  • 2Physical damage to the wiring harness: Wear to the A-pillar trim panel, headliner, or floor wiring harnesses during accident repairs, modifications (e.g., routing dash cam wiring), or long-term use damages wire insulation, causing a short to ground or short to power.
  • 3Connector fault: Water ingress, oxidation, corrosion, or terminal deformation at the airbag wiring harness connector inside the right front door sill trim panel or below the A-pillar, causing a short circuit between pins.
  • 4SRS ECU internal fault: Damage to the internal driver chip or sampling circuit in the airbag control unit triggers a false short circuit fault.
  • 5Improper repair operation: failing to disconnect the 12V battery negative terminal according to specifications during previous repairs, directly measuring the airbag circuit using a multimeter resistance setting (use a dedicated airbag resistor), or electrostatic discharge causing an igniter short circuit.
What To Do
  • 1
    Safety preparation: Switch the vehicle OFF, disconnect the 12V battery negative terminal, and wait at least 90 seconds to fully discharge the SRS ECU backup power supply and prevent accidental airbag deployment during repair.
  • 2
    Fault Confirmation and Freeze Frame Analysis: Connect the diagnostic tool to read the freeze frame data for DTC B1763. Record the vehicle speed, temperature, voltage, and other environmental conditions at the time of the fault to determine whether the fault is intermittent or continuous.
  • 3
    Visual inspection: Remove the right A-pillar trim, headliner edge, and right front door sill trim. Inspect the curtain airbag wiring harness connector (usually a yellow plug) for looseness, water ingress, burning, or aftermarket wire taps.
  • 4
    Harness continuity test: Disconnect the SRS ECU connector and the right front curtain airbag connector. Use a multimeter to measure the resistance to ground and resistance to power at the harness-side pins (SRS side and airbag side). The standard value must be greater than 1 MΩ. Measure harness continuity and confirm no short to ground or power.
  • 5
    Airbag module isolation test: Connect a dedicated airbag substitute resistor (2.0Ω) to the circuit in place of the right front curtain airbag. Connect the negative battery terminal, clear the fault code, and power on for a self-test. If the fault code disappears, the airbag inflator has an internal short circuit; replace the right front curtain airbag assembly. If the fault code remains, the fault is in the wiring harness or the ECU.
  • 6
    SRS ECU inspection: Check the ECU connector pins for corrosion or push-back. Measure the resistance of the corresponding drive port inside the ECU. If necessary, update the SRS control unit software or replace the ECU.
  • 7
    Repair and verification: After repairing or replacing the faulty component, reconnect all connectors and install the battery negative terminal. Use the diagnostic tool to clear the DTC and perform an SRS system self-test (center the steering wheel and ensure the vehicle is level). Finally, perform a road test to verify the SRS warning light turns off and the system generates no new fault codes.
Real-World Cases
BYD DTC AI Analysis

Song MAX right front curtain airbag short circuit after water ingress

✓
A 2019 Song MAX came in with the SRS light on after driving through heavy rain. DTC B1763 stored. Removed the right front A-pillar trim. Found the airbag circuit pins in the sill harness connector corroded from water ingress due to poor sealing, shorting the terminals (0.3Ω). Cleaned the connector with electronic contact cleaner, blew it dry, applied conductive grease, and replaced the waterproof seal. Fault cleared. Analysis: On flood-damaged vehicles, check the sealing of SRS harness connectors mounted low on the floor.
BYD DTC AI Analysis

Qin Pro modifications caused wiring harness chafing and short circuit

✓
The owner of a 2020 Qin Pro reported the SRS warning light illuminated with DTC B1763. Upon inquiry, the owner had recently installed a 360-degree camera system with wiring routed through the right-hand A-pillar. Inspection found the installer had pierced the factory SRS wiring harness insulation when securing cable clips, causing the airbag igniter wire to short to ground. Repaired damaged wiring using double-layer heat-shrink tubing, rerouted the harness to avoid sharp metal edges, cleared fault codes and restored normal operation. Note: Modifications involving the A-pillar or headliner require extra care to protect SRS wiring.
BYD DTC AI Analysis

Replaced airbag assembly due to internal short in igniter

✓
Case involves a 2019 BYD Song MAX with no accident history or modifications. After 30,000 km, the SRS warning light illuminated intermittently with DTC B1763. Disconnected the right-side roof curtain airbag connector and measured 0.1Ω across the airbag terminals (normal ~2.5Ω), indicating an internal short in the squib. Replaced the right front side curtain airbag assembly (requires headliner removal). Fault cleared. Root cause: Suspected moisture contamination of the propellant or a manufacturing defect caused the bridge wire to melt and short.
BYD DTC AI Analysis

SRS ECU false positive software fault

✓
A 2020 Qin petrol variant set a B1763 fault code. Airbag resistance and wiring harness measured normal. Consulted BYD TSB: early-batch SRS control unit software has a sampling error that triggers false short-circuit faults below 0°C. Fix: Updated SRS ECU software using VDS2000/3000 (version must be above V2.3). Fault has not returned since. Note: For short-circuit fault codes with normal measured values, suspect an ECU software bug.
Other Seal 6 EV 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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Seal 6 EV →Seal 6 EV 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.