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B167711

B167711 is a BYD Supplemental Restraint System (SRS) diagnostic code indicating a short to ground in the left rear side impact sensor signal circuit — Seal U

Safety System

B167711 is a BYD Supplemental Restraint System (SRS) diagnostic code indicating a short to ground in the left rear side impact sensor signal circuit.

This sensor typically mounts in the left B-pillar or C-pillar area.

It detects acceleration changes during a side impact and provides a collision severity signal to the Airbag Control Unit (ACU).

A short to ground indicates insulation failure between the sensor signal wire (SIG) or power wire (VB) and the vehicle body ground (GND), dropping the resistance below the normal threshold (typically <5Ω).

This fault prevents the ACU from receiving the collision signal, triggers the system fail-safe mechanism, disables deployment of the left rear side airbag and side curtain airbag, and illuminates the airbag warning light.

During a severe collision, the affected airbags may fail to inflate, posing a severe safety hazard.

5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Wiring harness physical damage: Long-term vibration, pinching, or chafing damages the sensor wiring harness insulation inside the left rear quarter trim panel, below the B-pillar, or near the seat rail. Contact with vehicle body metal causes a short to ground.
  • 2Internal sensor fault: Breakdown of the internal IC circuit, filter capacitor, or Zener diode in the crash sensor causes an internal short between the signal and ground terminals. Common causes include sensor aging or severe vibration.
  • 3Connector water ingress and corrosion: Vehicle wading, direct high-pressure washing, or aging seals allow water to enter the left rear side panel. This oxidizes and electrolytically corrodes the sensor connector pins (usually located below the B-pillar or inside the sill beam), creating a short-circuit path.
  • 4Improper repair work: During left rear accident repairs, window regulator repairs, or audio modifications, an improperly secured wiring harness allows screws or clips to crush the insulation, or an incompletely seated connector bends the terminal into contact with the metal frame.
  • 5SRS control unit internal fault: A short circuit in the filter capacitor of the ACU internal signal sampling circuit or a damaged AD converter causes the system to falsely detect an external sensor short to ground (relatively uncommon but requires inspection).
What To Do
  • 1
    Safety preparation: Park the vehicle on a level surface, turn the ignition switch to OFF, disconnect the 12V battery negative terminal, and wait at least 90 seconds to fully discharge the SRS capacitor and prevent accidental airbag deployment.
  • 2
    Fault confirmation: Use the BYD VDS2000/VDS3000 diagnostic tool to access the SRS system. Read DTC B167711 to confirm if the fault is current (Active), and record the freeze frame data (ambient temperature and vehicle status).
  • 3
    Visual inspection: Remove the left B-pillar lower trim panel and left rear door sill trim panel. Inspect the left rear side impact sensor (usually marked 'SRS SIDE SENSOR') for physical damage, cracks, or burn marks.
  • 4
    Circuit measurement: Disconnect the sensor connector. Use a multimeter to measure the resistance to ground for each terminal on the harness side: the power wire (+B) to ground should be infinite, and the signal wire (SIG) to ground should be >1MΩ. If the signal wire resistance to ground is <5Ω, inspect the wiring along the harness routing to the SRS control unit (usually located under the center console).
  • 5
    Sensor test: Remove the sensor and measure the resistance across its terminals. Resistance between power and ground must be a fixed value (typically several hundred ohms to several kΩ, depending on the model). Resistance between signal and ground must be a specific value. If the signal terminal has continuity to ground, replace the sensor.
  • 6
    Wiring harness repair: Inspect the protective corrugated conduit where the wiring harness passes through sheet metal holes and seat rail mounting points. Repair any damaged insulation using heat-shrink tubing or electrical tape, and re-secure the harness to prevent contact with sharp edges.
  • 7
    Component replacement: If testing confirms an internal short circuit, replace the left rear side impact sensor (Note: Use a part of the same model; sensor sensitivity curves vary by vehicle model). Install the sensor with the arrow pointing toward the front of the vehicle (impact direction).
  • 8
    System reset: Reconnect all connectors, reconnect the 12V battery negative terminal, use the diagnostic tool to clear the fault code, perform the 'SRS system self-check' and 'sensor calibration' (if applicable), and confirm B167711 does not return and the airbag warning light turns off.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Tang DM-i seat memory function inoperative

✓
Symptoms: While driving, the instrument cluster suddenly displayed 'Seat System Fault'. The driver's seat memory function failed completely—could not save or recall seat positions. After switching off and restarting, the fault code remained, though manual seat adjustment worked normally. Diagnosis: Connected the VDS2000 scan tool and retrieved code B167711 (Driver Seat Position Sensor Circuit Range/Performance). Inspected the wiring harness connector under the seat and found slight internal oxidation. Measured the seat position sensor resistance; it fluctuated between 2.5kΩ and 3.1kΩ (should be stable at 2.8kΩ ±0.2kΩ). Checked the seat memory module supply voltage: 13.8V, normal. CAN bus communication waveform was normal. Resolution: Replaced the driver's seat horizontal position sensor (Part No. F3-6826300). Ran the 'Seat Position Calibration' routine using the scan tool. Cleared the fault code and test drove the vehicle; seat memory function returned to normal.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Han EV Founding Edition: Automatic seat adjustment malfunction

✓
**Symptoms:** When using the comfort entry function, the seat suddenly jammed while automatically retracting, and the instrument cluster displayed 'Check Seat System'. The vehicle drove normally, but the seat position memory failed, returning the seat to the fully forward position every time the owner entered the vehicle. **Diagnosis:** Connected a diagnostic scanner and retrieved DTC B167711, stored as three historic faults. Removed the seat for inspection and found traces of spilled drink inside the seat rails with corrosion on the position sensor connector. Measured the sensor supply voltage at 5V (normal), but the signal wire voltage fluctuated between 0.3V and 2.8V (should show linear progression). Inspected the Seat Control Module (SCM) and found signs of water ingress internally. **Resolution:** Thoroughly cleaned the seat rails and wiring harness connectors, treated the connector pins with WD-40 Specialist Electrical Contact Cleaner, and replaced the seat position sensor. Dried out the Seat Control Module and applied waterproof sealing. Fault resolved.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Song Pro DM seat memory module communication fault

✓
After the vehicle sat overnight, the driver's seat automatically moved to the rearmost position upon startup the next morning. The memory buttons could not return the seat. The multimedia system displayed an abnormal seat position icon and the warning light illuminated. Diagnosis: Connected the BYD dedicated diagnostic tool and retrieved DTCs B167711 (seat position sensor signal invalid) and U024687 (lost communication with seat memory module). Inspected the seat memory module (located beneath the seat) power supply fuse and found poor contact at F2/14. Reseating the fuse restored communication, but B167711 remained. Further inspection revealed the seat position sensor wiring harness had chafed through at the seat rail, intermittently shorting to earth. Resolution: Repaired the damaged wiring harness (re-wrapped with insulation tape and protected with corrugated tubing), replaced the fuse, and performed the 'seat system self-learning' procedure using the diagnostic tool. Advised the owner to avoid placing hard objects under the seat to prevent harness damage.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Qin Plus DM-i seat position signal drift

✓
Symptoms: While driving, the instrument cluster occasionally displayed a 'Seat Position Abnormal' warning that cleared quickly. This later developed into erratic seat memory function, with saved positions deviating significantly from actual positions (approximately 5cm fore-aft deviation when recalled after saving). Diagnosis: Retrieved DTC B167711 as a historical fault with no current faults present. Observed live data and found seat fore-aft position sensor values fluctuating randomly between 128-135 (should vary linearly with seat movement). Inspected the sensor mounting bracket and found the fixing screws loose with excessive clearance between the sensor and rack. Measured sensor operating voltage and detected 0.3V ripple interference on the 5V reference. Resolution: Retightened the seat position sensor fixing screws and adjusted the sensor-to-rack clearance to 0.5-1.0mm. Fitted a ferrite core to the sensor signal line to suppress interference, cleared the adaptive values, and recalibrated the seat position. This completely resolved the fault.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Tang EV seat memory module software fault

✓
Symptoms: Three months after purchasing the new vehicle, the seat memory function developed an intermittent fault, occasionally accompanied by DTC B167711. The fault mostly occurred after the vehicle had been parked for extended periods (over 8 hours), and may clear itself after driving for a while. Diagnosis: Connected VDS and retrieved DTC B167711, but could not clear it. Inspected the seat position sensor and associated wiring harnesses; found no physical damage. Checked the seat memory module (SMJ) software version and found V1.02. Cross-referenced with the service bulletin and confirmed a software bug. Monitored the seat position sensor data stream and found the sensor failed to initialise after the vehicle woke from sleep mode. Resolution: Upgraded the seat memory module software to version V1.05. After the upgrade, performed a 'full seat system calibration' (including: learning the limit positions for horizontal travel, height adjustment, backrest angle, and cushion angle). Monitored the vehicle for one week following the upgrade; the fault has not reoccurred.
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. Sources: [1]