AU
B16DF-00

This fault code indicates the SRS (airbag) control unit detects a communication interruption or no connection with the Left Rear Impact Sensor — Seal 6 EV

Safety System

This fault code indicates the SRS (airbag) control unit detects a communication interruption or no connection with the Left Rear Impact Sensor.

This sensor typically mounts in the vehicle’s left rear side panel, C-pillar, or rear door area to monitor side-impact acceleration signals.

The SRS ECU triggers this fault if it fails to receive valid data from the sensor within a predetermined time, or if it detects circuit resistance outside the normal range (open or short circuit).

This fault disables the vehicle’s side-impact detection function.

The system may fail to accurately determine collision severity, suppressing normal deployment of the left rear side airbag/side curtain airbag.

In some cases, this creates a risk of unintended airbag deployment in fail-safe mode.

The B16DF-00 fault code on the Seal 6 EV indicates the SRS airbag control unit has lost communication with the left rear impact sensor. Severity is medium because side-impact detection and related airbag deployment may be affected. Common causes include damaged wiring near the rear side panel or door hinge, or a loose, corroded sensor connector. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
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Cases Logged
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Causes
Likely Causes — Seal 6 EV
  • 1Broken or crushed left rear impact sensor wiring harness, especially at bends passing through the door hinge or inside the sill trim panel where long-term vibration fractures the copper wires.
  • 2Loose sensor connector, backed-out terminals, or corrosion from water ingress. Poor sealing after wading or washing the vehicle commonly causes terminal oxidation.
  • 3Crash sensor internal accelerometer damage or circuit fault causes no signal output.
  • 4Internal detection circuit fault in the SRS control unit preventing correct identification of the sensor signal (less common)
  • 5Wiring harness accidentally cut or connector not fully seated during accident repairs or vehicle modifications (such as window tinting or audio system installation).
What To Do
  • 1
    Connect the BYD dedicated diagnostic tool (VDS or ED400), read all fault codes and freeze frame data, and verify the vehicle speed, timestamp, and other data recorded when the fault occurred.
  • 2
    Turn off the ignition, disconnect the negative battery terminal, and wait at least 90 seconds to completely discharge the SRS system high-voltage capacitor.
  • 3
    Remove the left rear interior trim panel (lower C-pillar trim panel or left rear door sill trim panel) and locate the left rear impact sensor (usually marked 'LEFT REAR' or 'LR').
  • 4
    Check the sensor connector for looseness or backed-out pins. Inspect the terminals for green corrosion or water marks. If necessary, clean the terminals with electrical contact cleaner and apply conductive grease.
  • 5
    Measure sensor wiring harness continuity with a multimeter: check the circuit resistance between the sensor connector and the SRS ECU (should be less than 1Ω), and check the insulation resistance to ground (should be greater than 1MΩ).
  • 6
    Measure the sensor internal resistance (refer to the standard value in the workshop manual, usually 2-5kΩ). If the resistance is infinite or zero, replace the sensor.
  • 7
    If the wiring harness is damaged, repair or replace the harness. Protect the harness with high-temperature corrugated conduit to prevent rubbing against metal body edges.
  • 8
    Reconnect all connectors, reconnect the battery negative terminal, turn the ignition ON, use the diagnostic tool to clear the fault code, and perform an SRS system self-diagnosis.
  • 9
    Perform a road test or simulated vibration test to confirm the fault code does not recur. Verify the instrument panel airbag warning light turns off normally.
Real-World Cases
BYD DTC AI Analysis

Qin EV450 left rear impact sensor fault after wading

✓
A 2018 BYD Qin EV450 came in with the airbag warning light on the instrument panel constantly on. Connected a VDS diagnostic scanner and retrieved DTC B16DF-00 (left rear impact sensor disconnected). Inspection found the left rear door had been exposed to water. Removed the left rear sill trim panel and found the impact sensor connector had visible water stains and copper oxide corrosion inside. Cleaned the connector terminals, dried the wiring harness with compressed air, applied waterproof sealant and reconnected the plug. Cleared the fault code and the system returned to normal operation.
BYD DTC AI Analysis

Loose sensor connection on BYD Qin 100 after accident repair

✓
2017 BYD Qin 100. The SRS warning light illuminated following right rear collision repairs. Diagnosis revealed DTC B16DF-00. Inspection found the left rear impact sensor connector was not fully seated during the repair disassembly, causing an intermittent connection from driving vibrations. Reseated connector and installed a retaining clip, then secured the wiring harness routing with cable ties. Fault resolved.
BYD DTC AI Analysis

Suspected B16DF-00 high-voltage battery contact fault case

✓
An EV reported DTC B16DF-00. The technician suspected abnormal resistance at the high-voltage battery front-end contacts and recommended checking the battery balancing status and front-end contact connections. Note: This case differs from the standard SRS sensor definition, possibly due to model year variations in DTC definitions or a false report by the battery management system under specific conditions.
Original source ↗
Other Seal 6 EV 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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Seal 6 EV →Seal 6 EV overview →
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.