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 — Seal U

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
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Causes
Likely Causes — Seal U
  • 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 system records.
  • 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.
  • 3Airbag Control Unit (ACU) software is outdated, or internal configuration data is corrupted/lost (e.g., due to prolonged vehicle power loss or discharged battery).
  • 4Use of a non-genuine seat (such as a modified seat) or aftermarket airbag assembly whose electrical characteristics do not match original factory configuration parameters.
  • 5A previous accident required replacing the ACU or wiring harness, 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 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 when the fault occurred (normal range: 2.0-3.0 Ω; an invalid configuration usually displays 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). Confirm the connector fully locks and shows no oxidation or corrosion. Inspect the connector pins for push-out. If necessary, clean the connector and apply special conductive grease.
  • 3
    Remove the seat side trim panel. 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 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 the 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 Seal U 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.