AU
B1762

DTC B1762 indicates the SRS (Supplemental Restraint System) detected a short to ground in the Left Front Side Curtain Airbag deployment circuit — Atto 3

Safety System

DTC B1762 indicates the SRS (Supplemental Restraint System) detected a short to ground in the Left Front Side Curtain Airbag deployment circuit.

Electrically, the side curtain airbag squib is a resistive load (typically 2-5 Ω).

The SRS ECU controls it via a twisted pair.

The ECU sets this code when it detects the circuit's insulation resistance to body ground falls below the threshold (typically <1 Ω) or when it detects abnormal ground voltage.

This fault indicates: 1) Positive or negative squib wiring shorted to body metal within the A-pillar, B-pillar, or C-pillar trim, or in the headliner harness; 2) Igniter bridge wire insulation failure inside the airbag module; 3) Driver MOSFET breakdown inside the SRS ECU.

This fault prevents the airbag from deploying during a collision (open-circuit protection mode) or, in extreme cases, creates a risk of unintended deployment.

Consequently, the ECU illuminates the airbag warning light and disables the system.

The B1762 fault code on the Atto 3 indicates a high-severity SRS fault: a short to ground in the left front side curtain airbag deployment circuit. Common causes include chafed wiring in the sill, pillar, or headliner area, or water ingress at the A- or B-pillar connector. The airbag warning light may come on and protection may be reduced. 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 — Atto 3
  • 1Harness chafing inside the sill trim panel: The left front curtain airbag harness routes from the SRS ECU along the floor sill to the roof. After sill trim panel removal and installation, or driving through water, a damaged harness protective sleeve causes the copper wire to contact the body metal.
  • 2Water ingress in the A-pillar/B-pillar connector: The side curtain airbag connector is located inside the A-pillar upper trim panel or B-pillar interior trim panel. Water leaking from a blocked sunroof drain tube or entering during a car wash causes a short circuit between the connector terminals or to ground.
  • 3Airbag module internal fault: Aging internal bridge wire insulation in the side curtain airbag igniter or a manufacturing defect causes a short to ground, typically associated with a history of use in high-humidity environments.
  • 4SRS ECU drive circuit fault: Breakdown of the ignition driver stage transistor inside the ECU causes a false short-to-ground detection. Measure the resistance between the ECU output terminal and ground to confirm.
  • 5Accident repair damage: After a side impact or roof repair, trim panel clips pinch the wiring harness, metal burrs cut the harness, or overtightened cable ties damage the insulation.
What To Do
  • 1
    Safe power isolation and system discharge: Turn off the ignition switch, disconnect the low-voltage battery negative terminal, and wait at least 5 minutes (10 minutes on some models) to fully discharge the SRS capacitor and prevent accidental airbag deployment.
  • 2
    Locate the physical connection point: Remove the left A-pillar upper trim panel, the left B-pillar interior trim panel, and the front edge of the headlining. Locate the dedicated yellow connector for the side curtain airbag (usually located above the A-pillar or B-pillar). Inspect the connector for oxidation, water ingress, or foreign objects.
  • 3
    Segmented resistance measurement: Disconnect the airbag module connector. Use a digital multimeter to measure the resistance between each of the two harness-side (ECU-side) wires and the vehicle body. If the resistance is <1 Ω, the circuit has a short to ground. If the resistance is infinite, short the two harness wires together and measure the airbag side. Continuity to ground indicates an internal short circuit in the airbag module.
  • 4
    Inspect the wiring harness section by section: If testing confirms a short circuit, open the corrugated conduit section by section from the ECU toward the airbag. Focus the inspection on the transition area between the door sill and the A-pillar, and the pinch points at the harness retaining clips. After locating the damage, repair it using double-layer heat-shrink tubing or replace the wiring harness assembly.
  • 5
    Component replacement verification: If the wiring harness is normal but the airbag module has an internal short circuit, replace the left front side curtain airbag module; for a suspected ECU fault, cross-check using a known-good ECU.
  • 6
    System reset and verification: After repairs, reconnect all connectors and the battery. Use the dedicated diagnostic tool to clear the fault code and perform an SRS system self-check (typically including static and dynamic tests). Verify DTC B1762 does not return and the airbag warning light turns off. Finally, perform a road test to verify the repair.
Real-World Cases
BYD DTC AI Analysis

Worn door sill wiring harness causes intermittent short circuit on Song MAX

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Vehicle: 2019 BYD Song MAX DM, 80,000 km. Symptoms: Airbag warning light comes on intermittently, with increased frequency in rain or on rough roads. Diagnosis: DTC B1762 stored as a history fault. Removed the left front sill trim and found the side curtain airbag wiring harness had chafed against the sill reinforcement beam retaining clip, wearing through the insulation to expose the copper wire. Over bumps, the wire contacted the body causing an intermittent short to ground. Solution: Repaired the damaged wiring with double-layer heat shrink tubing, rerouted the harness clear of sharp edges, and replaced the retaining clips with rubber-sleeved types. Fault resolved.
BYD DTC AI Analysis

Qin Pro EV A-pillar connector water ingress and corrosion

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Vehicle: Qin Pro EV 2019. Symptoms: Airbag warning light stayed on after heavy rain, accompanied by poor sunroof drainage. Diagnosis: Active fault B1762. Measured side curtain airbag harness resistance to ground at 0.3Ω. Inspection: Connector inside A-pillar upper trim showed green corrosion in the yellow plug; insulation resistance between terminals and to ground failed. Root cause: Sunroof left-front drain hose connector detached, letting rainwater run down the A-pillar into the connector. Solution: Cleaned and dried connector terminals, sprayed electronic contact cleaner, repaired drain hose connector, wrapped waterproof tape around the connector, and adjusted mounting angle to prevent water pooling. Fault cleared.
BYD DTC AI Analysis

Side Curtain Airbag Module Internal Short Circuit Replacement Case

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Vehicle: Song MAX petrol 2020 model, no accident history. Symptoms: Airbag warning light stays on; DTC B1762 cannot be cleared. Diagnosis: Disconnected the airbag module connector. Harness side ground resistance >10MΩ (normal). Both pins on the module side measure <1Ω to ground. Confirmed internal short to ground in the airbag igniter. Removed and inspected the airbag module (located in the left roof rail); found the internal bridge wire shorted to the metal housing. Resolution: Replaced the left front side curtain airbag assembly (including inflator), performed configuration coding. System back to normal.
BYD DTC AI Analysis

Short circuit from improperly secured wiring harness after accident repair

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Vehicle: 2020 BYD Qin Fuel, left front previously scraped in a collision. Symptoms: B1762 fault code appeared one month post-repair. Diagnosis: During the accident repair, the technician failed to route the side curtain airbag harness into the dedicated wire channel when installing the B-pillar trim panel, instead pinching it under the trim clips. Over time, the sharp clip edges cut through the harness insulation, causing a short to ground. Solution: Rerouted the harness, installed OEM harness retaining clips, repaired the damaged insulation. Fault cleared.
Other Atto 3 Fault Codes
P0AA6Hybrid Battery Voltage System Isolation FaultB1108For 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.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.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.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.
Common problems reported for Atto 3 →Atto 3 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.