AU
B1611

DTC B1611 indicates a short to ground in the front passenger airbag (PAB) ignition circuit — Atto 3

Safety System

DTC B1611 indicates a short to ground in the front passenger airbag (PAB) ignition circuit.

Specifically, the SRS control unit detects an abnormally low-resistance connection (typically less than 2-3Ω) between the passenger airbag inflator circuit (usually the high-level trigger wire) and vehicle ground (GND).

This short circuit prevents normal airbag deployment (diverting ignition energy to ground) or, in extreme cases, causes inadvertent deployment due to static electricity or electromagnetic interference.

This fault constitutes a severe active safety system failure.

The SRS control unit immediately disables the front passenger airbag, illuminates the airbag warning light, and may simultaneously lock the seat belt pretensioner, severely compromising passive safety performance.

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Cases Logged
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Causes
Likely Causes — Atto 3
  • 1Passenger-side dashboard wiring harness wear: Where the airbag wiring harness passes through the dashboard frame or near the steering column, long-term vibration damages the insulation, causing contact with the metal body and creating a short to ground.
  • 2Connector water ingress and corrosion: The airbag connector (usually yellow) located under the centre console or on the floor is poorly sealed. Wading through water or an A/C condensate leak causes electrolytic corrosion between the pins, resulting in a short to ground.
  • 3Repair damage: Tools scratching or crushing the wiring harness during cabin air filter replacement, radio replacement, or dashboard removal and installation, causing damaged wire insulation to contact metal body parts.
  • 4Airbag module internal fault: Damaged igniter bridge wire insulation inside the front passenger airbag assembly shorts the ignition terminal to the airbag metal housing (ground). This condition usually indicates previous moisture ingress into the airbag assembly.
  • 5Rodent damage: During long-term outdoor or warehouse parking, rodents chew through the wiring harness insulation, exposing the copper core and causing contact with the body ground.
What To Do
  • 1
    Safety preparation and diagnostic confirmation: Disconnect the battery negative terminal and wait at least 90 seconds to fully discharge the SRS capacitor. Read freeze frame data using the diagnostic tool to confirm vehicle conditions at the time of the fault (temperature, vehicle speed, etc.). Check for accompanying fault codes (e.g., B1610, B1612).
  • 2
    Visual inspection and connector check: Remove the lower trim panel under the front passenger glovebox. Inspect the yellow SRS connector (usually marked F-PAB) for water ingress, corrosion, or deformed pins. Measure the resistance from the connector terminals to ground. Normal resistance is greater than 10 MΩ.
  • 3
    Harness continuity check: Test continuity of the harness from the SRS ECU to the front passenger airbag. Focus on sections passing through the Cross Car Beam and the floor harness sleeve. Use an endoscope to inspect the harness for wear at metal edges.
  • 4
    Airbag module test: Replace the front passenger airbag with a dedicated airbag simulator (2Ω load). Clear the fault code and power on the vehicle. If the fault code does not return, the airbag assembly has an internal short circuit. Replace the front passenger airbag module.
  • 5
    Repair and verification: Repair the damaged wiring harness (wrap with double-layer heat-shrink tubing for insulation). Secure the wiring harness, maintaining a minimum 20mm clearance from metal components. Apply conductive paste and reconnect all connectors. Connect the battery. Use the diagnostic tool to perform 'System Configuration' and 'Sensor Calibration'. Finally, perform a collision simulation test to verify fault resolution.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Song MAX dashboard wiring harness wear caused intermittent short circuit

✓
A 2019 BYD Song MAX with 32,000 km had an intermittent airbag warning light and DTC B1611. Technicians found the passenger side airbag wiring harness had chafed through at the dashboard crossmember clip due to prolonged vibration, exposing the copper core. When the vehicle encountered bumps or temperature fluctuations, the exposed wiring contacted the crossmember causing a short to earth. Technicians repaired the damaged wiring (approximately 15 cm), rerouted the harness away from sharp edges, and fitted a rubber protective sleeve. This permanently resolved the fault.
BYD DTC AI AnalysisFrom Chinese market (translated)

Tang DM air conditioning condensate leak corroded connector

✓
2021 Tang DM. After heavy rain, the airbag warning light stayed on. Scan tool read DTC B1611 and could not clear it. Inspection found obvious water stains on the passenger-side floor harness connector (beneath the evaporator box). Resistance between Pin 1 (airbag high signal) and the connector shell (ground) was only 0.8 Ω. Traced to a blocked AC drain hose causing condensate to back up. Repair: cleaned and dried connector, treated pins with WD-40 Precision Electrical Cleaner, cleared drain hose, and applied sealant around the connector.
BYD DTC AI AnalysisFrom Chinese market (translated)

Yuan EV wiring harness improperly secured after accident repair

✓
One week after completing front collision repairs on a 2019 Yuan EV, the vehicle logged a B1611 DTC. Service history showed a previous replacement of the instrument panel assembly. Inspection found the passenger airbag harness pinched between the instrument panel bracket and body shell during reinstallation, crushing the insulation and creating an earth short. Replaced the damaged harness section (from instrument panel main harness to airbag connector). Reinstalled the instrument panel to the workshop manual torque of 9.8 N·m and fitted dedicated harness clips to maintain safe clearance from metal components.
BYD DTC AI AnalysisFrom Chinese market (translated)

Long-term parking caused rodents to chew the wiring harness on the Qin Pro.

✓
2020 Qin Pro. After sitting parked in a rural yard for two weeks, the airbag warning light illuminated on startup. Diagnosis revealed DTC B1611. Inspection of the wiring passthrough between the engine bay and passenger cabin found the harness sheath chewed through, with multiple bite marks on the internal airbag wiring. One wire had exposed copper contacting the body metal. Repair: cut out the damaged section, soldered in an extension wire, and insulated the repair with double-layer heat shrink tubing. Installed metal rodent-proof mesh at the wiring grommet and applied capsaicin-based rodent repellent to the harness surface.
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. Sources: [1]