AU
B168A00

DTC B168A00 indicates the Airbag Control Unit (ACU) detects the configuration parameters for Circuit 6 (typically the right side airbag/side curtain or right rear side airbag ignition circuit) do not match the system calibration data — Seal U

Safety System

DTC B168A00 indicates the Airbag Control Unit (ACU) detects the configuration parameters for Circuit 6 (typically the right side airbag/side curtain or right rear side airbag ignition circuit) do not match the system calibration data.

This is an SRS configuration fault, not a simple open or short circuit. "Invalid configuration" means the control unit's internal algorithm detects the circuit's electrical characteristics (such as squib resistance, capacitance, or internal ECU configuration code) differ from the vehicle factory settings or current hardware configuration.

This condition can prevent the airbag from deploying correctly or cause unintended deployment during a collision, constituting a Level 2 safety fault.

5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Incorrect coding configuration after Airbag Control Unit (ACU) replacement, or software version mismatch.
  • 2Installed a non-genuine or incorrectly programmed side airbag module (aftermarket or used part with a mismatched part number).
  • 3Modifications or accident repairs to the Circuit 6 wiring harness changed the circuit impedance (e.g., installing aftermarket seat covers, pinched wiring, or oxidized connectors causing resistance to deviate from the 2.0Ω±0.3Ω standard range).
  • 4Calibration data stored in the SRS control unit is lost or corrupted (e.g., prolonged battery disconnection, electromagnetic interference affecting the ECU).
  • 5Vehicle configuration changed (e.g., replacing high-spec parts with low-spec parts) without updating the ACU configuration code.
What To Do
  • 1
    Use the BYD VDS2000/VDS3100 diagnostic tool to read complete fault codes and freeze frame data, confirm the fault frequency (current/history), and record the vehicle VIN and specific configuration.
  • 2
    Refer to the vehicle repair manual to identify the specific component corresponding to Circuit 6 (for the Qin PRO, this is typically the right side airbag or right curtain airbag). Inspect the component appearance, connector condition, and wiring harness integrity.
  • 3
    Disconnect the battery negative terminal, wait 3 minutes, then disconnect the SRS control unit connector. Measure the resistance between the two terminals of circuit 6 using a multimeter (standard value: 1.7-2.3 Ω), and check the insulation to ground and power.
  • 4
    If the resistance is abnormal, inspect the wiring harness and airbag module section by section. If the resistance is normal, use the diagnostic tool to perform the 'Airbag System Configuration' function, then verify and rewrite the correct vehicle configuration code (select options such as with/without side airbags and curtain airbags based on the actual vehicle configuration).
  • 5
    Execute the "Configuration Reset" or "ECU Initialization" procedure. Clear the fault code, then perform a system self-check (turn the ignition switch ON and observe if the airbag warning light stays on for 6 seconds and then turns off). Finally, perform a simulated crash test or road test to verify the fault is resolved.
Real-World Cases
BYD DTC AI Analysis

BYD Qin Pro DM logged DTC B168A00 after fitting a salvage ACU.

✓
After accident repairs, technicians fitted a 2019 Qin PRO DM with a used airbag control unit from another vehicle. Once installed, the instrument panel airbag warning light stayed on, and they read DTC B168A00. Diagnosis revealed the replacement ACU stored a base model configuration code (without side curtain airbags), while the vehicle actually had side curtain airbags. They used the VDS diagnostic tool to execute the ‘Replace SRS ECU’ function, rewriting the vehicle’s VIN and high-spec model configuration code. This cleared the fault.
BYD DTC AI Analysis

Right front seat modification caused circuit 6 impedance fault

✓
The owner of a 2018 Qin PRO petrol variant reported the airbag warning light occasionally coming on. Retrieved DTC B168A00. Inspection found the owner had previously fitted full-coverage seat covers; the fastening clips had pierced the right front seat side airbag harness, causing circuit 6 resistance to fluctuate between 1.2–3.5Ω. Repaired the harness and remeasured resistance at 2.0Ω. Cleared the DTC and no faults returned after 3 days of use.
BYD DTC AI Analysis

Software version too low to recognise new components

✓
After the dealership replaced the right side airbag module, a 2019 Qin PRO DM set DTC B168A00. Replacing the module multiple times did not resolve the issue. Inspection found the ACU software was an early 2018 version, while the new airbag module had an improved igniter design. Solution: Upgraded the SRS control unit software to the latest version (post-October 2019), reconfigured the loop parameters, and resolved the fault.
BYD DTC AI Analysis

Oxidised SRS connector on flood-damaged vehicle caused configuration failure

✓
Repaired a Qin PRO DM that had been driven through water. Afterwards, the airbag warning light came on with DTC B168A00. Found water inside the lower right B-pillar SRS harness connector; oxidised and blackened pins increased contact resistance to 4.5 Ω, causing the control unit to misread as 'invalid configuration'. Cleaned the connector and applied conductive paste; resistance then measured 1.9 Ω. Cleared the fault code and the system returned to normal.
BYD DTC AI Analysis

A wiring harness bridge repair after an accident caused a fault.

✓
While repairing right-side accident damage on a Qin PRO, a workshop incorrectly cross-connected the Loop 6 (side airbag) and Loop 5 (the other side airbag) wiring harnesses. This caused the ACU to detect that the electrical characteristics of Loop 6 did not match the stored configuration template. After reconnecting the harnesses according to the circuit diagram to ensure the left and right circuits were independent and had normal resistance, the fault code cleared automatically.
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.