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B16F700

For BYD Qin PRO (2018–2019) models, DTC B16F700 indicates a "Sensor line 1 configuration error" in the SRS (Supplemental Restraint System/airbag system) — Seal U

Safety System

For BYD Qin PRO (2018–2019) models, DTC B16F700 indicates a "Sensor line 1 configuration error" in the SRS (Supplemental Restraint System/airbag system). "Line 1" typically refers to the main power wire, signal wire, or CAN communication line of a crash sensor (e.g., front or side impact sensor).

This fault indicates the ACU (Airbag Control Unit) detects the sensor circuit's electrical configuration does not match the calibration parameters.

Possible causes include incorrect pin assignments, incorrect wiring harness connection order, or incorrect coding and matching after sensor replacement.

This safety-critical fault disables the related airbag circuit, preventing deployment during a collision.

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Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Failure to perform the 'Sensor Configuration' or 'Coding' procedure using the VDS diagnostic tool after replacing the crash sensor or airbag control module results in a configuration parameter mismatch.
  • 2Incorrectly pinned sensor wiring harness connector during repair (e.g., reversed CAN High and CAN Low wires, or incorrect power and signal pin positions) causes a circuit logic configuration error.
  • 3Incorrect sensor part number installed (e.g., high-spec model sensor installed on a low-spec model); hardware pin assignment does not match the vehicle wiring harness.
  • 4Configuration data stored internally in the SRS control module (ACU) is corrupted or missing, typically due to battery discharge, electromagnetic interference, or module failure.
  • 5Swapping the left and right sensor connectors after vehicle accident repairs (e.g., reversing the left front and right front sensor connectors) causes the system to detect a configuration logic error.
What To Do
  • 1
    Connect the VDS2000/VDS1000 diagnostic tool and enter the SRS (airbag) system. Read and record all fault codes. Confirm B16F700 is a current fault, not a history fault, and check for other related sensor fault codes.
  • 2
    Refer to the workshop manual to locate the specific sensor corresponding to 'Line 1' (usually the left front impact sensor or driver-side side impact sensor). Check that the wiring harness connector colour and pin positions match the standard configuration. Confirm there are no backed-out or misaligned pins.
  • 3
    Disconnect the battery negative terminal and wait 3 minutes for the SRS system to discharge. Measure the resistance to ground and continuity of each pin at the sensor harness connector to confirm there are no short circuits, open circuits, or crossed wires.
  • 4
    Check the sensor part number against the vehicle BOM to confirm the sensor hardware configuration is correct. For a newly replaced sensor, perform the 'Sensor Replacement Coding' or 'Configuration Write' function to write the correct sensor parameters into the ACU.
  • 5
    If configuration writing fails, check the ACU software version and upgrade the ACU program if necessary. Verify the wiring harness shield ground to rule out configuration recognition errors caused by electromagnetic interference.
  • 6
    After completing the configuration, reconnect the battery, clear the fault code, and perform the SRS system self-check (turn the ignition switch ON and observe if the airbag warning lamp on the instrument cluster turns off after the self-check). Perform a road test or simulation test to confirm the fault is resolved.
Real-World Cases
BYD DTC AI Analysis

Incorrect left front crash sensor configuration causing airbag light on Qin Pro DM

✓
Symptoms: The airbag warning light on the instrument cluster of a 2018 Qin PRO DM stays on constantly. VDS read DTC B16F700 (Sensor Line 1 Configuration Error). Diagnosis: Inspection of the left front impact sensor connector revealed a non-genuine sensor had been installed during a previous accident repair. The pin configuration did not match the original vehicle wiring harness — the high and low CAN pins were reversed. Repair: Replaced the left front impact sensor with a genuine unit, performed the 'Sensor Configuration' routine using VDS, and cleared the fault codes. The airbag light turned off and the system self-test passed.
BYD DTC AI Analysis

Qin Pro petrol version SRS module data loss causing configuration error

✓
Symptoms: 2019 Qin PRO petrol vehicle started after sitting for one week; instrument cluster displayed ‘Check Airbag System’ and logged DTC B16F700. Diagnosis: Inspected sensor wiring — no physical damage. Voltage measured normal. Determined the ACU lost internal configuration data. Repair: Disconnected the battery for 30 minutes to reset the ACU. After reconnecting power, used VDS to perform ‘System Configuration Restore’. Cleared the fault code; it has not returned.
BYD DTC AI Analysis

Qin Pro DM: Replacing the airbag control module without configuring it causes a fault.

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Symptoms: After a water ingress incident, the Airbag Control Unit (ACU) was replaced. After fitting the new module, the VDS reported fault code B16F700 and multiple sensor configuration errors. Diagnosis: The replacement ACU was a blank module that had not been programmed with vehicle-specific configuration parameters. Resolution: Accessed 'Special Functions' > 'ACU Configuration' through the VDS, entered the VIN and configuration codes, and configured each sensor parameter individually (including the first-line configuration). The faults cleared upon completion.
BYD DTC AI Analysis

Song/Tang models B16F700 Left Front Headlight Fault Case (Note: Definition varies by model)

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Symptoms: BYD Song/Tang instrument cluster displays 'Check Body Control System', left headlight inoperative or flickering. VDS reads BCM DTC B16F700 (Left Front Combination Lamp Fault). Diagnosis: Inspected the left headlight wiring harness connector and found water ingress and corrosion; the pin configuration did not match the BCM output. Repair: Cleaned the connector, applied conductive grease, and replaced the damaged wiring harness. Some cases required replacement of the headlight assembly or BCM. Note: This case shows that on some non-Qin Pro models, B16F700 is defined as a body control system fault, unlike the Qin Pro where it is part of the SRS definition.
Original source ↗
BYD DTC AI Analysis

Qin series body control system fault case (model definition differences)

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Symptoms: The instrument cluster on Qin Pro and Qin PLUS models displays the message "Check Body Control System" along with a left headlight malfunction. VDS reads that the BCM stores DTC B16F700. Diagnosis: Inspection of the connection between the front compartment wiring harness and headlight revealed harness damage from aftermarket modifications or backed-out pins in the headlight connector. Repair: Repaired or replaced the damaged wiring harness and recalibrated the lighting system. Note: The same fault code may point to different systems across different model years.
Original source ↗
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.