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B162212

DTC B162212 indicates abnormal continuity between the squib circuit of the driver side airbag (usually the seat-mounted side airbag) and the vehicle positive power supply (B+, battery voltage) — Atto 8

Safety System

DTC B162212 indicates abnormal continuity between the squib circuit of the driver side airbag (usually the seat-mounted side airbag) and the vehicle positive power supply (B+, battery voltage).

In the SRS (Supplemental Restraint System) control logic, the airbag squib circuit must maintain a high-impedance open state at rest.

The control unit determines circuit integrity by monitoring circuit voltage.

Detecting a short to power in this circuit indicates damaged wiring insulation contacting a constant power wire, or an insulation failure of the igniter coil inside the airbag module.

This fault immediately forces the SRS into fail-safe mode, which: 1) Disables the driver side airbag, preventing deployment during a side impact; 2) Illuminates the airbag warning lamp; 3) Creates a risk of unintended airbag deployment in extreme cases (despite multiple protections in modern systems).

Because it involves a core component of the passive safety system, this fault classifies as severe and requires immediate repair.

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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Mechanical damage to the under-seat wiring harness: The driver-side side airbag wiring harness moves back and forth with the seat. Repeated bending or crushing by foreign objects (such as coins or toys) wears through the insulation, causing a short circuit to the seat heater wire or constant power wire.
  • 2Water ingress and corrosion in the SRS connector: When driving the vehicle through water or cleaning the interior, liquid enters the dedicated yellow SRS connector under the seat, causing an electrolytic short circuit between the terminals, or verdigris creates continuity between the power terminal and the airbag circuit terminal.
  • 3Airbag module internal short circuit: Aging, static electricity, or manufacturing defects damage the igniter (squib) internal coil insulation, causing the primary coil to contact the secondary coil or housing and create a short to power.
  • 4Improper post-accident repair: Failing to replace the damaged wiring harness to specification after a collision or using non-genuine parts causes incorrect wire routing, placing the airbag circuit parallel to the power supply circuit with insufficient insulation.
  • 5SRS control unit internal fault: A damaged MOSFET or sampling resistor in the control unit's internal monitoring circuit falsely reports a short to power, or an internal drive circuit fault actually shorts the circuit to power.
What To Do
  • 1
    Safe power-down: Turn off the ignition, disconnect the negative battery cable, and wait at least 3 minutes (some models require 90 seconds, but BYD SRS capacitor discharge usually takes 3 minutes) to fully discharge the system.
  • 2
    Fault status confirmation: Connect the BYD dedicated diagnostic tool (VDS2000 or EDT), enter the SRS system to read fault codes, confirm B162212 is a current fault (Current DTC), and check the voltage value in the freeze frame data (usually displaying 12V or battery voltage).
  • 3
    Visual and physical inspection: Check the yellow SRS connector under the driver's seat (usually on the outer side of the seat rail or at the seat base) for signs of water ingress, terminal corrosion, and bent pins. Inspect the wiring harness for wear or damaged insulation within the seat's range of movement.
  • 4
    Circuit isolation test: Disconnect the driver-side airbag module connector (requires removing the seat side trim panel or backrest cover). Use the special shorting bar to short the harness-side connector and measure the harness-side voltage. If battery voltage remains, the fault is in the wiring harness. If the voltage is 0V, the fault is in the airbag module.
  • 5
    Harness continuity check: Disconnect the SRS control unit connector (usually located in the center tunnel or under the dashboard). Use a multimeter to measure continuity between the driver side airbag ignition wire (usually a yellow harness; consult the wiring diagram for pin assignments) and power (B+) and ground to check for short circuits.
  • 6
    Insulation resistance measurement: Use a megohmmeter (500V range) to measure the insulation resistance between the airbag ignition circuit and other power supply circuits. Normal resistance is greater than 10MΩ. A reading below 1MΩ confirms insulation damage.
  • 7
    Component replacement verification: If testing confirms an internal short circuit in the airbag module, replace the driver side airbag module (Note: use certified replacement parts of the same model and batch). If testing confirms a wiring harness fault, repair the damaged section and reinforce the protection using corrugated conduit and fabric tape. Leave sufficient wiring length, especially at seat movement points.
  • 8
    System reset and matching: Reconnect all connectors, connect the battery, and turn the ignition switch to ON (do not start). Use the diagnostic tool to clear fault codes and perform an SRS system self-diagnosis. Some models require a 'Configuration and Setting' or 'Coding' procedure to write the new airbag module parameters.
  • 9
    Function verification: Confirm the airbag warning light turns off after the 6-second self-check. Read the data stream to verify the 'driver side airbag resistance' is between 2.0-3.0Ω and the voltage is 0V (static). Move the seat forward and backward to confirm no wiring harness interference.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Seat adjustment chafed the wiring harness, causing a short circuit.

✓
Model: Qin Pro DM 2019. Customer reported the airbag warning light staying on. Scan tool read current DTC B162212. Inspection revealed the wiring harness under the driver's seat was pinched when the seat track was in the fully forward position. The yellow airbag wire insulation had chafed through and contacted the red seat heater power wire, causing a short circuit. Repair: replaced the entire damaged harness section, rerouted the cable path, added protective sleeving at flex points, and ensured no interference through full seat travel. After clearing the DTC, the system returned to normal. Resistance: 2.4Ω.
BYD DTC AI AnalysisFrom Chinese market (translated)

Connector corroded and shorted after wading

✓
Vehicle: BYD E2 2019. The vehicle waded through water about 30 cm deep, after which the SRS warning light came on. DTCs B162212 and B162213 (short to ground) appeared alternately. Removed the driver's seat and found the SRS connector (yellow) contained obvious water stains and corrosion; insulation resistance between terminals had dropped to 0.5 MΩ. Repair: Cleaned the connector using precision electrical contact cleaner, blew it dry, applied specialised electrical contact protectant, and replaced the waterproof seal. The airbag module sustained no damage, and the fault cleared after the repair. Recommend checking the vehicle floor sealing.
BYD DTC AI AnalysisFrom Chinese market (translated)

Wiring incorrectly connected after accident repair

✓
Vehicle: Qin EV 2019. After left front collision repairs, the airbag warning light stayed on. DTC B162212 retrieved. Inspection found that during the repair, an unauthorised workshop swapped the side airbag and seat heater connectors when replacing the seat (same pin count, different colours). This connected the airbag circuit directly to 12V power. Fix: Corrected the connector connections, checked the airbag module (resistance measured 2.2Ω, normal), cleared the fault codes, and the system returned to normal. Note: BYD SRS connectors have mechanical keying; forcing them may cause damage.
BYD DTC AI AnalysisFrom Chinese market (translated)

Replaced airbag module due to internal short circuit

✓
Vehicle: BYD E3 2020. The airbag warning light illuminated suddenly while driving without collision impact. Fault code B162212. Disconnected the SRS control unit in the engine compartment and the wiring harness under the seat. Measured separately: the wiring harness side showed good insulation to ground and to power supply (>20MΩ), with infinite resistance. At the airbag module side, measured continuity between the igniter terminals and the housing, confirming an internal short circuit. Repair: Replaced the driver's seat side airbag module (required dismantling the seat backrest; gas generator retaining torque: 7.5 N·m). Performed online matching and programming after replacement. Fault 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. Sources: [1]