AU
B167B11

DTC B167B11 has different definitions depending on the vehicle model — Seal U

Safety System

DTC B167B11 has different definitions depending on the vehicle model.

Early models, such as the BYD E2, E3, and Qin EV, define this fault as a short to ground in the right rear side impact sensor (SIS) signal circuit within the SRS airbag system.

Newer models, such as the Han EV, define it as a short to ground in the left front seat heater circuit.

Regardless of the application, sub-code '11' indicates a short to ground.

For the SRS system, this fault indicates the airbag control unit (ACU) continuously detects 0V on the right rear side impact sensor signal wire (below the 0.3V threshold), preventing the ACU from receiving the correct collision acceleration signal.

This triggers the SRS fail-safe mode, constituting a serious safety hazard.

The fault may prevent the side airbag or side curtain from deploying correctly during a side impact, or falsely trigger the airbag warning lamp while driving.

For the seat heater definition, this fault indicates the heating element circuit current increased abnormally, causing the control module to activate overcurrent protection.

The B167B11 fault code on the Seal U indicates a short to ground in the left front seat heater circuit, causing the system to activate overcurrent protection. Severity is high. Common causes include wiring harness insulation worn by contacting metal components, or water ingress corroding connectors. Visit an authorised dealer for repair. Typical repair cost data is available based on 4 recorded cases.
4
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Right rear side impact sensor wiring harness insulation worn, contacting the body sheet metal or seat frame and causing a short to ground (commonly caused by improperly securing the harness after removing and installing the rear fender liner).
  • 2Water ingress and corrosion in the sensor connector causing the signal pin to short to ground (common after vehicle wading, car wash fluid residue, or seal aging).
  • 3Crash sensor internal electronic component failure causing a signal line short to ground (internal capacitor breakdown or IC damage)
  • 4Seat slide rails, retaining screws, or clips crushed and damaged the wiring harness during removal or installation of the rear seat or C-pillar trim panel.
  • 5During rear quarter panel collision repairs, sheet metal edges cut the wiring harness or damaged insulation at a mounting point, causing a short to body ground.
What To Do
  • 1
    Safety preparation: Disconnect the 12V battery negative terminal and wait at least 90 seconds (to fully discharge the SRS system capacitors) to prevent accidental airbag deployment. Wear an anti-static wrist strap.
  • 2
    Locate the sensor: Remove the right rear C-pillar trim panel and rear fender liner, then find the right rear side impact sensor (usually above the rear sill beam, at the lower section of the C-pillar, or behind the rear seat backrest).
  • 3
    Visual inspection: Check the sensor connector for looseness, water ingress, or corroded or bent pins. Check the wiring harness conduit for wear, damaged insulation, or crush marks.
  • 4
    Circuit measurement: Use a multimeter to measure the resistance to ground of the sensor signal wire (usually the 5V reference voltage circuit provided by the ACU). The standard value must be greater than 10MΩ. A reading close to 0Ω confirms a short to ground.
  • 5
    Segmented diagnosis: Disconnect the sensor connector. Measure the resistance to ground on the wiring harness side (from the ACU) and the sensor side separately to determine whether the short circuit is in the wiring harness or internal to the sensor.
  • 6
    Wiring harness repair: If the wiring harness is damaged, cut out the damaged section. Re-solder or crimp the terminals. Use dual-wall heat-shrink tubing (adhesive-lined inner layer) for waterproof insulation. Re-secure the wiring harness to prevent interference.
  • 7
    Component replacement: If the sensor has an internal short circuit, replace the right rear side impact sensor. (Note: Use genuine parts. Typical installation torque is 8-10 N·m. Do not overtighten to prevent housing damage.)
  • 8
    System verification: Restore connections, turn on the power, use the VDS diagnostic tool to clear the fault code, and perform an SRS system self-check (requires static and dynamic road test verification). Confirm the fault code does not return and the airbag warning light turns off.
Real-World Cases
BYD DTC AI Analysis

BYD Song MAX left front heated seat failure (similar fault code B16A311)

✓
Symptoms: Dashboard displayed 'Seat system fault'. Left front seat heating failed; pressing the heater switch caused the indicator to flash for 3 seconds, then extinguish. Diagnosis: Scanned with VDS and retrieved B16A311 (Left front seat heater circuit short to earth). Measured heating pad resistance at 0.5 Ω (specification 2-5 Ω). Found the seat rail pinching the wiring harness, causing the heater element to short to earth. Fix: Replaced the left front seat heating pad assembly (S6J-6807100). Repaired and rerouted the wiring harness. Adjusted the seat rail stops.
Original source ↗
BYD DTC AI Analysis

BYD Qin Pro DM Seat Control Module Communication Fault (DTC B167111/B167B11)

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Symptoms: Instrument cluster intermittently displayed "Please check seat system", driver's electric seat adjustment occasionally failed, and seat memory positions were lost. The fault appeared easily on rough roads. Diagnosis: Read DTC B167111 (seat control module communication fault) and historical code B167B11. Measured CAN-H voltage to ground: 0.3V (standard 2.5-3.5V). Found the wiring harness retaining clip under the seat had detached; the harness rubbed against the seat rail and wore through, causing the CAN-H wire and heater power wire to short to ground simultaneously. Fix: Repaired the CAN-H and heater power wires, applied heat shrink tubing for waterproofing, replaced the wiring harness retaining clip, and recalibrated the seat memory positions.
Original source ↗
BYD DTC AI Analysis

BYD Tang DM front seat heating automatically turns off (DTC B168311)

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Symptoms: Heated seats switch off automatically after 3–5 minutes. The instrument cluster displays 'Seat Heating System Fault' and both front heated seats are inoperative. The vehicle had previously been driven through water. Diagnosis: Retrieved DTC B168311 (Right Front Seat Heater Circuit Short to Ground) and historical code B167B11. Inspected the seat heating control module (located beneath the right front seat) and found water staining and corrosion. Measured the resistance of the right front heating pad to ground at 0.2 Ω (short circuit); the left front reading was normal. Resolution: Replaced the right front seat heating pad and control module. Removed the seat, cleared accumulated water from the seat frame, and applied rust inhibitor. Checked the floor wiring harness for water exposure.
Original source ↗
BYD DTC AI Analysis

BYD Han EV heated seat low setting inoperative (DTC B167B11/B167C11)

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Symptoms: Left front seat heater only operates on the high setting; selecting low automatically reverts to off, with the climate panel displaying "Seat Fault". Diagnosis: Retrieved DTCs B167B11 (Left Front Seat Heater Circuit Short to Ground) and B167C11. Measured the low-setting heating element shorted to ground at 0.1 ohms; the high setting measured normal. Disassembly found the heating pad delaminated and aged, with the low-setting heating wire shifted and contacting the seat metal frame. The retention tape also deteriorated and detached from heat exposure. Resolution: Replaced the left front seat heating pad with an upgraded unit featuring optimised heating element retention, fitted a mica heat shield, and flashed the seat control module to software version 2023V03.
Original source ↗
Other Seal U Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.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.B173712DTC B173712 indicates a short to power in the firing circuit of the right second-row side airbag module in the Supplemental Restraint System (SRS). Specifically, the "right second-row side airbag" typically refers to the side impact airbag located in the right B-pillar or the side of the right seat. The "12" suffix indicates a circuit short to battery positive (B+). This fault causes the following conditions: 1) The airbag may fail to ignite and deploy during a collision, resulting in a loss of side impact protection. 2) In extreme cases, unintended triggering may cause accidental airbag deployment. 3) The SRS control unit detects abnormally high circuit voltage (typically above 4.5V) and enters fault protection mode. This may disable the entire airbag system and continuously illuminate the instrument cluster airbag warning light.
Common problems reported for Seal U →Seal U 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.