AU
B170000

DTC B170000 indicates a configuration error on circuit 4 (typically the configuration identification line, backup signal line, or sensor type identification line) of the Supplemental Restraint System (SRS) crash or acceleration sensor — Seal U

Safety System

DTC B170000 indicates a configuration error on circuit 4 (typically the configuration identification line, backup signal line, or sensor type identification line) of the Supplemental Restraint System (SRS) crash or acceleration sensor.

The SRS control unit detects that the connected sensor hardware model, wiring harness pin assignment, or internal coding data does not match the preset system configuration.

Circuit 4 typically handles sensor identification, redundant signal transmission, or address coding.

Incorrect circuit connections, incorrect sensor models (e.g., installing a left-side sensor on the right side or using a sensor from an incompatible model year), or incorrect control module software calibration trigger this fault.

This prevents the SRS from accurately determining the crash sensor status, potentially causing the airbags to fail to deploy during a collision or to deploy unintentionally.

This is a safety-critical fault.

4
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Mismatched collision sensor installed: Installing a non-genuine part or a sensor for the wrong model year/specification (e.g., fitting a DM version sensor to a petrol version, or swapping the left and right sensors) causes the signal on the fourth identification wire to differ from the ECU expected value.
  • 2Incorrect pin insertion during wiring harness repair or modification: During accident repair or wiring modification, sensor connector pin 4 (usually the configuration or identification wire) and an adjacent pin swap positions, or the wiring harness has a short or open circuit.
  • 3SRS control module software version mismatch: Control unit software not updated to match current hardware configuration, or sensor parameter configuration/coding missing after control module replacement.
  • 4Internal sensor configuration data corrupted: Electromagnetic interference, abnormal voltage, or physical impact corrupts the configuration data stored in the crash sensor’s internal EEPROM, causing the fourth wire to transmit an incorrect identification code.
  • 5Multi-sensor system address conflict: On vehicles equipped with multiple crash sensors, two sensors share the same address code, causing a data conflict on the fourth wire (communication/address wire).
What To Do
  • 1
    Use the BYD dedicated diagnostic tool (VDS2000/VDS3100) to read the complete fault code stream, confirm whether B170000 is a current fault, check for accompanying fault codes (such as B16FF12 or other circuit short faults), and record the freeze frame data.
  • 2
    Visually inspect the physical condition of the relevant crash sensor (front crash sensor, side crash sensor, or center sensor) and confirm no external damage. Check the connector for looseness, water ingress, or corrosion, and confirm the wiring harness is not crushed or damaged.
  • 3
    Check the sensor part number: Remove the sensor and check the part number, production date, and applicable model code on the label against the BYD EPC system. Confirm they match the vehicle VIN (note the differences between the Qin PRO DM and fuel versions, and the left and right positions).
  • 4
    Measure the electrical parameters of the fourth wire: Disconnect the sensor and ECU connectors. Use a multimeter to measure the resistance between the fourth wire and ground, power, and other pins (resistance should be greater than 10 MΩ). Check harness continuity (resistance should be less than 1 Ω) to confirm no short or open circuit.
  • 5
    Check pin assignment: Refer to the workshop manual wiring diagram. Confirm pin 4 of the sensor connector matches the corresponding SRS control module pin assignment. Check for backed-out, bent, or misaligned pins.
  • 6
    Perform sensor configuration/coding: After verifying the hardware, use the diagnostic tool to enter the SRS system special functions. Execute the 'Sensor Configuration' or 'Crash Sensor Coding' procedure and follow the prompts to enter the correct sensor serial number or select the correct configuration parameters.
  • 7
    Software update: Check if the SRS control module has the latest software version. If available, perform the update to ensure the control unit software is compatible with the hardware configuration.
  • 8
    Clear the fault code and verify: After completing the repair, clear the fault code and perform an ignition cycle test to confirm the fault code does not reappear. Use the diagnostic tool to read the sensor data stream and confirm the fourth wire status displays 'Normal' or 'Configured'.
Real-World Cases
BYD DTC AI Analysis

Replaced sensor with a used part on Qin Pro DM, causing configuration error

✓
A 2019 Qin PRO DM had its front crash sensor replaced with a unit salvaged from another vehicle following a minor front-end collision. Once fitted, the airbag warning light illuminated on the instrument cluster. Scanning revealed DTC B170000 (sensor fourth wire configuration error). Diagnosis showed the salvaged sensor had part number EF-3636100 (fits 2020 models), whereas this vehicle requires EF-3636000 (fits 2019 models). The fourth wire function differs between versions: it serves as an identification line on 2019 models and a communication line on 2020 models. Replaced it with a genuine sensor of the correct part number, performed the sensor configuration procedure, and cleared the fault.
BYD DTC AI Analysis

Misaligned pins after wiring harness repair caused the fault

✓
2018 BYD Qin Pro petrol. SRS warning light stayed on after accident repairs. Fault codes B170000 and B16FF12 were stored. Inspection found the left front impact sensor harness damaged in the accident. When re-crimping the connector, the technician swapped pin 4 (yellow wire, configuration line) and pin 3 (signal line). This caused the ECU to detect an abnormal voltage on wire 4 (always high). Corrected the pin positions per the wiring diagram, cleared the fault codes, and the system returned to normal.
BYD DTC AI Analysis

Outdated SRS module software causing false alarm

✓
The airbag warning light came on for no apparent reason during normal driving on a 2019 Qin Pro DM with no accident history. The scan tool retrieved DTC B170000. The sensor connector and wiring harness checked out fine, and the voltage on the fourth wire measured 2.5 V (within specification). A TSB search revealed a software bug in the SRS control module for this production batch that could cause false sensor configuration errors when ambient temperature dropped below -5 °C. Upgrading the SRS module software from V1.2 to V1.5 completely resolved the fault.
BYD DTC AI Analysis

Side impact sensors fitted on wrong sides (left and right reversed)

✓
A 2018 Qin Pro displayed an airbag warning on the instrument cluster after both side airbags were replaced. Stored fault codes were B170000 and B170100 (right sensor fourth wire configuration error). Inspection found the technician had installed the left B-pillar impact sensor (part number suffix -L) and the right sensor (suffix -R) in reversed positions. Although the connectors are identical, the internal address resistor values on the fourth wire differ (left 1.2kΩ, right 2.4kΩ). The ECU detected the address code from the sensor at the right-side position did not match the expected left-side value. After swapping the sensors to their correct positions, the fault was eliminated.
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.