AU
B168E00

DTC B168E00 indicates an invalid configuration in Ignition Loop 10 of the Supplemental Restraint System (SRS) — Atto 8

Safety System

DTC B168E00 indicates an invalid configuration in Ignition Loop 10 of the Supplemental Restraint System (SRS).

On the BYD Qin PRO, Loop 10 typically corresponds to the ignition circuit for the right seat belt pretensioner or the right side curtain airbag. "Invalid configuration" means the SRS control unit detects a circuit resistance outside the standard range (2.0-3.0Ω), or the stored configuration data does not match the installed hardware.

This fault prevents the corresponding airbag or pretensioner from deploying normally during a collision.

The system also illuminates the airbag warning lamp and may disable the entire SRS, severely impacting passive safety performance.

3
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Abnormal internal resistance in the seat belt pretensioner or airbag module (short or open circuit), causing circuit resistance to deviate from the standard value (normal: 2-3Ω; below 1Ω is a short circuit; above 6Ω is an open circuit).
  • 2Poor contact at the wiring harness connector, corrosion from water ingress, or backed-out pins causing unstable circuit resistance or communication faults.
  • 3SRS control unit (ACU) internal configuration data is missing, corrupted, or does not match the vehicle hardware configuration (e.g., failing to perform online coding or write configuration parameters after replacing the control unit).
  • 4Short circuit in the return circuit wiring caused by improper operation during modification or repair (e.g., piercing the wiring harness when installing seat covers), or non-standard bridging of airbag-related wiring.
  • 5A fault in the crash sensor or related peripheral components causes the control unit to falsely detect an abnormal circuit status.
What To Do
  • 1
    Use the BYD VDS diagnostic tool to read the complete fault code and freeze frame data. Verify the environmental conditions at the time of the fault (temperature, voltage, etc.) and attempt to clear the fault code. If the fault code is intermittent, check the trigger conditions in the history log.
  • 2
    Refer to the BYD Qin PRO workshop manual wiring diagram to identify the specific component for circuit 10 (typically the right front seat belt pretensioner R19 or the right curtain airbag). Disconnect the battery negative terminal and wait 3 minutes. Unplug the SRS control unit connector and measure the resistance between the circuit 10 pins.
  • 3
    Measure pretensioner/airbag connector resistance: Disconnect the corresponding component connector and measure the resistance directly between the two component terminals. The standard value is 2.0-3.0 Ω. A reading of 0 Ω indicates an internal short circuit. A reading of ∞ or greater than 6 Ω indicates an internal open circuit or wiring fault.
  • 4
    Check wiring harness continuity and insulation: Measure wiring continuity between the SRS control unit connector and the component connector (less than 1 Ω), and measure wiring insulation resistance to ground and power (greater than 10 MΩ). Carefully inspect the wiring harness under the seat (often worn by seat movement) and the B-pillar connector.
  • 5
    If wiring and components are normal, use VDS to perform the 'SRS System Configuration' or 'Online Coding' function and rewrite the control unit configuration data. Some models require entering the vehicle VIN or security configuration code. Once complete, clear the fault codes and perform a system self-check.
  • 6
    If the above steps fail, replace the SRS control unit (ACU) or the faulty component (pretensioner/airbag module). After replacement, perform online configuration and collision threshold setting. Finally, conduct a road test and verify the warning light turns off.
Real-World Cases
BYD DTC AI Analysis

Qin PRO DM: oxidised connector on the right front seat pretensioner causing intermittent fault.

✓
A 2019 BYD Qin Pro DM intermittently displayed 'Check SRS System' on the instrument cluster. VDS retrieved DTC B168E00 (current but clearable). Inspection found green oxidation inside the yellow pretensioner connector under the right front seat, suspected water ingress during washing or wading. Cleaned the connector, applied conductive grease, and the circuit resistance returned to 2.3Ω. Cleared the DTC and followed up for one week — no recurrence.
BYD DTC AI Analysis

Not coding the airbag control module after replacement caused an invalid configuration.

✓
2018 Qin Pro (petrol variant). After crash repair, replaced the SRS control unit with a new one. After installation, DTC B168E00 set and would not clear. Diagnosis found the new control unit was in a blank state — vehicle-specific configuration data (airbag count, pretensioner configuration, etc.) not programmed. Used the BYD VDS to perform 'Online Programming and Configuration'. Entered the vehicle VIN, and the matching data downloaded automatically. The fault code cleared successfully, and the system self-test passed.
BYD DTC AI Analysis

Aftermarket seat modification pierced the wiring loom, causing a short circuit.

✓
While installing leather seat covers, securing clips pierced the wiring harness beneath the right front seat, causing circuit 10 to short to ground (measured resistance 0.5Ω). DTC B168E00 remained active and could not be cleared. Stripped back the harness insulation and found two wires with damaged insulation touching each other. Re-wrapped the harness and repositioned the clips. Measured normal insulation resistance. 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.