AU
B162A-00

DTC B162A-00 indicates an abnormal left front seat side airbag ignition circuit resistance of 0 ohms, representing a short-to-ground fault — Atto 3

Safety System

DTC B162A-00 indicates an abnormal left front seat side airbag ignition circuit resistance of 0 ohms, representing a short-to-ground fault.

Normal airbag inflator resistance is 2.0-3.0 Ω.

A 0 Ω reading means the ignition circuit shorts to the vehicle body ground.

Potential causes include an internal airbag module short circuit, damaged wiring harness insulation shorting to ground, or shorted connector terminals.

This fault causes the SRS system to detect a risk of accidental ignition or deployment failure.

Consequently, the SRS system disables the airbag's collision protection function and illuminates the airbag warning light on the instrument cluster.

4
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Seat side airbag igniter internal short circuit (airbag module bridge wire short circuit or moisture in pyrotechnic charge)
  • 2Long-term adjustment friction damaged the wiring harness insulation under the seat or on the side of the backrest, causing a short circuit to the metal frame.
  • 3Water ingress, oxidation, corrosion, or bent pins in the seat side airbag connector (usually located under or on the side of the seat) causing a short circuit between the positive and negative terminals.
  • 4Internal fault in the SRS control unit sampling circuit causing a false low resistance fault.
  • 5Driving the vehicle through water, or directly spraying the side of the seat with a high-pressure washer during a car wash, causes water ingress and a short circuit in the connector.
What To Do
  • 1
    Safety preparation: Turn off the ignition switch and disconnect the 12V battery negative terminal. Wait at least 90 seconds for the SRS backup power supply capacitor to discharge completely, preventing accidental airbag deployment.
  • 2
    Freeze frame: Use the BYD VDS diagnostic tool to read the freeze frame data. Record the vehicle speed, temperature, voltage, and other environmental parameters at the time of the fault to determine if it is intermittent.
  • 3
    Visual inspection: Remove the left front seat assembly. Closely inspect the seat back side airbag label area and the wiring harness under the seat for wear, crushing, damaged insulation, water ingress, or signs of modification.
  • 4
    Resistance measurement: Disconnect the SRS ECU connector (located at the lower center console or center tunnel). Use a multimeter to measure the resistance of the left front seat side airbag circuit (refer to the workshop manual for pin assignments). Normal resistance is 2.0-3.0 Ω. A reading near 0 Ω confirms a short circuit.
  • 5
    Sectional isolation: Disconnect the seat side airbag connector. Measure the resistance between the two airbag assembly terminals (to determine if the airbag is internally shorted) and the harness-side resistance to ground (to determine if the harness is shorted to ground).
  • 6
    Insulation test: Use a megohmmeter to measure the insulation resistance between the wiring harness and body ground. The standard value must be greater than 1 MΩ.
  • 7
    Repair or Replace: If the airbag has an internal short circuit, replace the entire seat side airbag module (non-repairable). If the wiring harness is damaged, repair it and install corrugated conduit. Adjust the harness routing to ensure no interference throughout the full seat fore-and-aft adjustment range.
  • 8
    System verification: Restore connections, install the battery, turn the ignition ON, use VDS to clear the fault code, and perform the SRS system self-test (wait 30 seconds with the vehicle stationary). Confirm B162A-00 does not return and the airbag warning lamp turns off.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Seat rail adjustment caused wiring harness to chafe and short circuit

✓
2018 BYD Qin EV450, airbag warning light on. Read DTC B162A-00. Removed and inspected the left front seat and found the side airbag wiring harness pinched at the frontmost position of the seat track. Long-term front/rear seat adjustment had worn through the insulation, exposing copper wires that contacted the metal seat frame and shorted to ground. Repair: Repaired the damaged harness, wrapped it with high-temperature tape, and re-secured the harness routing. Added cable clips at both ends of the seat track to provide enough slack during adjustment and prevent contact with metal parts.
BYD DTC AI AnalysisFrom Chinese market (translated)

Water ingress during car washing caused the connector to short circuit.

✓
A 2019 E1 developed fault code B162A-00 after a car wash in wet weather. Inspection found the left front seat side airbag connector (near the carpet at the seat base) had an aged seal. Water got into the connector during high-pressure washing, shorting the terminals. The fault was intermittent—disappearing after drying out but returning after subsequent washes. Fix: Replaced the connector seal, cleaned and dried the terminals, applied conductive anti-corrosion grease, and repositioned the wiring harness away from low spots where water collects.
BYD DTC AI AnalysisFrom Chinese market (translated)

Short circuit in seat side airbag igniter

✓
A 2017 Qin 100 with no accident history had the airbag warning light suddenly illuminate on the instrument cluster. VDS displayed DTC B162A-00. Removed the left front seat side airbag module (located on the side of the seat backrest) and disconnected the connector. Measured 0.2Ω resistance between the airbag component terminals, confirming a short circuit in the internal igniter bridge wire. Suspected moisture ingress into the airbag propellant or a manufacturing defect. Repair: Replaced the left front seat side airbag assembly (the complete airbag module must be replaced and cannot be repaired separately). After replacement, performed system configuration and self-check.
BYD DTC AI AnalysisFrom Chinese market (translated)

Installing seat covers caused the connector to come loose and short-circuit.

✓
A 2018 Qin EV450 developed a fault after the owner fitted full-coverage seat covers. The technician found that forced pulling during installation had loosened the seat side airbag connector (yellow plug). The force deformed the internal terminals, causing them to touch and create a short circuit. The seat cover clips had also secured the wiring harness too tightly, restricting normal movement. Reinstalled and locked the connector. Replaced the deformed terminals. Adjusted the wiring harness length to prevent strain during seat adjustment. Advised the owner to use seat covers with dedicated airbag cutouts.
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]