AU
B167A

DTC B167A indicates the SRS (Supplemental Restraint System) ECU detects a communication interruption or physical disconnection of the Right Rear Side Impact Sensor (SIS) — Qin Plus

Safety System

DTC B167A indicates the SRS (Supplemental Restraint System) ECU detects a communication interruption or physical disconnection of the Right Rear Side Impact Sensor (SIS).

This sensor mounts in the right C-pillar area or near the rear door frame to monitor collision acceleration signals from the right rear of the vehicle.

The SRS ECU sets this DTC if it fails to receive a valid signal from the sensor within the specified detection period, or if it detects circuit resistance outside the calibrated range (open circuit ∞Ω or short circuit 0Ω).

This safety-critical fault severely compromises rear occupant side-impact protection.

During a right-side collision, it may cause the side and curtain airbags to fail to deploy or deploy with incorrect timing.

The B167A fault code on the Qin Plus indicates the airbag system has lost communication with the right rear side impact sensor, compromising side-impact protection for rear passengers. This medium severity issue is commonly caused by loose wiring connectors or damaged harnesses. You should visit an authorised dealer for inspection and repair. Typical repair cost data is available based on 4 recorded cases.
4
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Sensor wiring harness connector is loose, disconnected, or has poor contact (commonly occurs after accident repairs, improper seating after interior trim removal, or plug loosening due to prolonged driving on rough roads).
  • 2Wiring harness open or short circuit (harness damage caused by frequent friction during rear passenger entry and exit, crushing by luggage or vehicle collisions, or rodent bites)
  • 3Internal fault in the sensor body (accelerometer element aging, cracked internal solder joints, moisture ingress, or physical impact damage preventing signal output)
  • 4Abnormal resistance in the communication circuit between the SRS ECU and the sensor (wiring oxidation or loose connection causing signal attenuation or interference)
  • 5Water intrusion into the connector during vehicle wading or washing causes pin oxidation and corrosion, resulting in high resistance and poor contact.
What To Do
  • 1
    Safety preparation: Switch the vehicle to OFF, disconnect the negative battery terminal, and wait at least 3 minutes to ensure the SRS system capacitors fully discharge and prevent accidental airbag deployment.
  • 2
    Fault Confirmation: Read fault codes using the BYD dedicated diagnostic tool (VDS2000/VDS6000). Confirm B167A is a Current DTC, not a history DTC. Check for accompanying SRS-related fault codes (such as B1675, B1676, etc.).
  • 3
    Physical inspection: Remove the right rear C-pillar trim panel or rear seat side trim panel (depending on vehicle model). Locate the right rear side impact sensor (usually marked SRS-SIS-RR or similar) and visually inspect the connector for looseness, disconnection, water ingress, or oxidation.
  • 4
    Circuit measurement: Disconnect the sensor connector and use a multimeter to measure the wiring harness side: reference voltage (usually 5V±0.25V), ground circuit continuity (<2Ω), and signal circuit continuity. Measure the sensor body resistance (normal range approximately 2-5kΩ; refer to the vehicle repair manual for exact specifications).
  • 5
    Wiring harness repair: If the wiring harness has an open circuit, short circuit, or oxidized connector, repair the wiring harness (solder and insulate with heat-shrink tubing), clean the connector contacts (use electrical contact cleaner), and replace the connector if necessary.
  • 6
    Component replacement: If wiring harness measurements are normal but the fault persists, replace the right rear side impact sensor (Note: For some models, verify the part number matches. During installation, point the arrow toward the front of the vehicle).
  • 7
    System reset: Reconnect all connectors, connect the battery, and clear the fault codes. Turn the ignition switch to ON and verify the SRS warning lamp turns off after 6 seconds. Use the diagnostic tool to confirm B167A is a history fault or is cleared.
Real-World Cases
BYD DTC AI Analysis

BYD Song MAX: Loose connector after accident repair

✓
2019 Song MAX. Following accident repair to the right rear wing, the airbag warning light remained constantly on. Scanned with VDS and retrieved DTC B167A (current fault). Removed the right rear C-pillar trim and discovered the side impact sensor connector had not fully seated after the body repair, sitting partially dislodged and causing poor contact. Reinserted the connector until the locking tab clicked, secured the wiring harness with cable ties to prevent it working loose again, cleared the fault codes, and the SRS light went out. Fault resolved.
BYD DTC AI Analysis

Water wading caused sensor connector oxidation on a BYD Yuan EV.

✓
2019 Yuan EV. Airbag warning light came on after driving through floodwaters in heavy rain. Scan tool showed current fault code B167A. Inspection found poor sealing of the right rear sill wiring harness grommet. Water ingress caused severe oxidation and blackening of the pins inside the side impact sensor connector (white 2-pin connector), with green copper corrosion present. Cleaned the connector contacts thoroughly using electronic cleaner, applied dielectric grease (insulating silicone grease), replaced the grommet and resealed. Cleared the fault.
BYD DTC AI Analysis

BYD Tang DM wiring harness chafed through after prolonged wear, open circuit

✓
2021 Tang DM. At 50,000 km the SRS warning light illuminated intermittently, and DTC B167A appeared intermittently. Disassembly found the wiring harness on the inner side of the right rear door frame seal had rubbed against a metal bracket edge from repeated door operation, damaging the insulation. Three internal copper wires had broken completely, with only a few strands still making contact. Cut out the damaged section, soldered in extension wires, applied double-layer heat-shrink tubing, and rerouted the harness away from the sharp edge. Fault fully resolved.
BYD DTC AI Analysis

BYD Qin Pro sensor internal fault

✓
2020 Qin Pro, no accident history. Airbag warning light suddenly came on. Diagnostic scanner read current fault B167A. Checked the connector — secure. Measured harness supply voltage: 5V (normal). Ground normal, continuity normal. Diagnosed as internal accelerometer or conditioning circuit fault in the sensor. Replaced the right rear side impact sensor (part number must match VIN). Cleared fault codes and performed SRS self‑test; warning light went out, system returned to normal.
Other Qin Plus 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.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.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.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 Qin Plus →Qin Plus 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.