AU
B168F00

DTC B168F00 indicates the Airbag Control Unit (ACU) detects the configuration data for ignition circuit 11 (typically the driver-side seat side airbag or left seat belt pretensioner circuit) does not match the actual vehicle configuration — Atto 3

Safety System

DTC B168F00 indicates the Airbag Control Unit (ACU) detects the configuration data for ignition circuit 11 (typically the driver-side seat side airbag or left seat belt pretensioner circuit) does not match the actual vehicle configuration.

On the BYD Qin PRO, circuit 11 typically corresponds to the side airbag module built into the driver seat.

This fault occurs when configuration parameters stored in the ACU (such as airbag resistance threshold, serial number, and installation status) do not match the actual detected circuit characteristics.

This mismatch can prevent the airbag from deploying properly during a collision or trigger the system to enter a safety downgrade mode (cutting power to the circuit).

Common causes include replacing the seat assembly, ACU, or wiring harness without performing online configuration (Coding), or a loose wiring harness connector under the seat preventing the ACU from correctly identifying the airbag module.

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Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Replacing the driver seat assembly (including the side airbag) without performing online configuration or coding in the ACU causes the new airbag resistance/ID to mismatch the system records.
  • 2Loose or oxidized under-seat SRS wiring harness connector (yellow connector) or backed-out pins, causing abnormal circuit resistance and leading the ACU to falsely detect a configuration fault.
  • 3Airbag Control Unit (ACU) software version is outdated, or internally stored configuration data is corrupted/lost (e.g., due to prolonged vehicle power loss or a discharged battery).
  • 4Use of a non-genuine seat (such as a modified seat) or aftermarket airbag assembly with electrical characteristics that do not match original factory specifications.
  • 5A previous accident resulted in ACU or wiring harness replacement, and the repair process failed to execute the correct configuration writing procedure (failure to configure the airbag system using VDS).
What To Do
  • 1
    Use the BYD VDS2000 or Launch X-431 diagnostic tool to access the SRS system, read the freeze frame data, and confirm the Circuit 11 resistance value at the time of the fault (Normal range: 2.0-3.0 Ω; invalid configurations usually display 0 Ω or >10 Ω).
  • 2
    Check the yellow SRS wiring harness connector under the driver's seat (usually located on the inner side of the seat rail). Verify the connector locks fully and shows no oxidation or corrosion. Inspect for backed-out connector pins. If necessary, clean and apply special conductive grease.
  • 3
    Remove the seat side cover and measure the resistance of circuit No. 11 (side airbag) to verify the airbag assembly has no short or open circuits. If the resistance is abnormal, replace the airbag assembly.
  • 4
    Perform ACU online configuration: Using VDS, select 'Special Functions' → 'Airbag System Configuration' → enter the vehicle VIN or select the correct vehicle configuration code (select the configuration with or without side airbags based on the specific model year), and write the correct circuit configuration to the ACU.
  • 5
    If the configuration write fails or the fault recurs, check the ACU power supply (constant +12V) and ground. If necessary, update the ACU software to the latest version (such as the SRS software patch released after 2020), or replace and reconfigure the ACU.
  • 6
    Clear the fault code, perform an SRS system self-check (turn ignition switch ON, wait for SRS warning lamp to turn off), and perform a simulated crash test (use the diagnostic tool to execute 'Crash Output Test') to verify Circuit 11 status returns to normal.
Real-World Cases
BYD DTC AI Analysis

B168F00 fault after replacing driver's seat on Qin Pro DM

✓
A 2019 Qin PRO DM had the driver's seat assembly (including side airbag) replaced at a dealership. After the replacement, the SRS warning light on the instrument panel remained on, and DTC B168F00 was stored. Technicians found the new seat airbag connector was plugged in, but the ACU still stored the old seat airbag's ID. Using VDS, they performed the 'Airbag System Online Configuration' procedure, selected 'Replace Seat Airbag', entered the new airbag serial number, and cleared the fault code. The SRS light then returned to normal.
BYD DTC AI Analysis

Oxidised seat wiring harness connector causes intermittent configuration error

✓
The owner of a 2018 BYD Qin Pro petrol version reported the SRS warning light occasionally illuminating. Diagnosis revealed intermittent DTC B168F00. Inspection found green oxide inside the yellow SRS wiring harness connector beneath the driver's seat, causing circuit resistance to fluctuate between 2.5Ω and 8Ω. The ACU misinterpreted this as an invalid configuration. The technician cleaned the connector pins, applied conductive grease, and secured the wiring harness with cable ties to prevent movement. The fault has not reoccurred.
Original source ↗
BYD DTC AI Analysis

ACU configuration lost after accident repairs

✓
A collision-repaired Qin PRO DM had its airbag control unit (ACU) and some airbags replaced. After the repair, DTC B168F00 appeared. Diagnosis found the new ACU had no vehicle-specific configuration (blank by default). Using VDS, the technician performed the 'ECU Replacement' procedure, downloading the original configuration data for this VIN from the BYD server and writing it to the ACU. After completing matching and calibration for all airbag circuits, the fault cleared.
BYD DTC AI Analysis

Aftermarket seats triggered Circuit 11 configuration mismatch

✓
The owner fitted aftermarket sports seats (lacking side airbags or with mismatched airbag resistance), causing the ACU to detect infinite resistance in circuit 11 (open circuit) and trigger DTC B168F00 (Invalid Configuration). Reverting to the factory seats resolved the fault. Technical tip: If modifying seats, retain the factory airbags and ensure resistance matching (using a dedicated 2.7Ω decoding resistor), or disable that circuit in the ACU (requires manufacturer authorisation).
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.