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 — Qin Plus

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.

The B168F00 fault code on the Qin Plus indicates the airbag control unit detects a configuration mismatch for the driver-side seat airbag circuit, preventing proper deployment. Severity is medium. Common causes include failing to recode the system after seat replacement or loose under-seat wiring connectors. Visit an authorised dealer for configuration and inspection. Typical repair cost data is available from 4 recorded cases.
4
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Failure to perform online configuration or coding in the ACU after replacing the driver seat assembly (including side airbag), causing the new airbag resistance/ID to mismatch the system record.
  • 2The under-seat SRS wiring harness connector (yellow connector) is loose, oxidized, or has backed-out pins, causing abnormal circuit resistance and leading the ACU to falsely detect a configuration error.
  • 3Outdated Airbag Control Unit (ACU) software version, or corrupted/lost internal configuration data (e.g., due to prolonged vehicle power loss or a discharged battery).
  • 4Installed non-OEM seat (such as a modified seat) or aftermarket airbag component has electrical characteristics that do not match OEM configuration parameters.
  • 5A previous accident resulted in ACU or wiring harness replacement, and the technician failed to perform the correct configuration writing procedure during repair (did not use VDS to configure the airbag system).
What To Do
  • 1
    Use a BYD VDS2000 or Launch X-431 diagnostic tool to access the SRS system and read the freeze frame data. Verify the Circuit 11 resistance value when the fault occurred (normal range: 2.0-3.0 Ω; invalid configurations typically display 0 Ω or >10 Ω).
  • 2
    Check the yellow SRS wiring harness connector under the driver's seat (usually on the inner side of the seat slide rail). Verify the connector is fully locked and free of oxidation or corrosion. Check for backed-out pins. Clean and apply special conductive grease if necessary.
  • 3
    Remove the seat side trim panel and measure the resistance of circuit 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), then write the correct circuit configuration to the ACU.
  • 5
    If configuration writing 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 an SRS software patch released after 2020), or replace and reconfigure the ACU.
  • 6
    Clear the fault code, perform an SRS system self-check (ignition switch ON, wait for the 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 Qin Plus 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.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.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.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.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Qin Plus →Qin Plus 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.