AU
B167E00

This DTC indicates interrupted data communication between the Airbag Control Unit (ACU) and the right rear Side Impact Sensor (SIS) — Seal U

Safety System

This DTC indicates interrupted data communication between the Airbag Control Unit (ACU) and the right rear Side Impact Sensor (SIS).

The sensor typically mounts inside the right rear door trim panel or below the C-pillar and connects to the ACU via a LIN bus or hardwire connection.

The fault occurs when the ACU fails to receive a valid data frame from the sensor within the specified time window (typically 100-500ms) or receives incorrect checksum data.

Consequently, the ACU cannot obtain real-time collision acceleration data from the vehicle's right rear, directly affecting the deployment logic for the side and curtain airbags.

The system enters fail-safe mode, illuminates the airbag warning lamp, and may disable the right-side airbag circuit.

This condition can prevent proper airbag deployment during a side collision, posing a severe safety risk.

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Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Long-term repeated bending of the right rear door wiring harness at the door hinge causes internal wire breakage or insulation damage, resulting in a LIN line open circuit or intermittent poor contact.
  • 2Water ingress and oxidation at the sensor connector (commonly resulting from vehicle wading, high-pressure car wash fluid penetration, or aging door seals), causing a short circuit between terminals or increased resistance.
  • 3Right rear side impact sensor internal fault (e.g., damaged MEMS accelerometer chip, communication IC fault, or internal power supply circuit failure)
  • 4LIN bus circuit shorted to ground or power, or abnormal increase in circuit resistance (greater than 2 Ω), causing communication signal attenuation.
  • 5SRS control unit internal communication interface driver circuit fault (uncommon, usually occurs with multiple sensor communication fault codes)
What To Do
  • 1
    Use a BYD VDS 2000 or Launch X431 diagnostic tool to read all DTCs. Confirm if B167E00 is a current or historical fault, and check for accompanying B167D00 (parameter error) or U-series communication fault codes.
  • 2
    Disconnect the battery negative terminal and wait 3 minutes to allow the SRS system capacitor to discharge. Remove the right rear door trim panel. Visually inspect the side impact sensor (part number usually starts with 95920-) for secure mounting and physical damage.
  • 3
    Disconnect the sensor connector. Check the terminals for backed-out pins, corrosion, signs of water ingress, or looseness. Clean the terminals with electrical contact cleaner. Measure the resistance between the connector terminal and ground (should be less than 1 Ω).
  • 4
    Keep the ignition switch OFF. Measure the voltage to ground (normal: approximately 8-12V) and the waveform (should be a 12V square wave) of the LIN line (usually pink/green) at the sensor harness-side connector. Measure the continuity between the ground wire (black) and body ground (should be less than 0.5 Ω).
  • 5
    Carefully inspect the door wiring harness for wear at the hinge. Peel back the corrugated conduit and check for broken wires. If a wire is broken, repair it using a waterproof solder joint and add a protective sleeve for reinforcement.
  • 6
    Perform a component swap test: Swap the right rear sensor with the left rear sensor. If the fault code transfers to the left side (B167C00 appears), the sensor is faulty. Replace the sensor.
  • 7
    After repairing the wiring harness or replacing the sensor, reconnect the battery. Use the diagnostic tool to clear the fault code and perform the 'SRS System Calibration' or 'Crash Sensor Configuration' procedure (if applicable).
  • 8
    Perform a system self-check: Turn the ignition switch on and off 3 times in succession and confirm the airbag warning light turns off after the self-check. Perform a road test or simulated vibration test and confirm the fault does not recur.
Real-World Cases
BYD DTC AI Analysis

Qin Pro DM right rear door wiring harness broke at the hinge, causing communication interruption.

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Model: 2019 Qin PRO DM, Mileage: 32,000 km. Symptoms: Airbag warning light illuminated intermittently while driving and extinguished after stopping and restarting; frequent on rainy days. Diagnosis: Retrieved DTC B167E00 (current). Measured sensor power supply as normal, but LIN bus voltage fluctuated between 5-9V (unstable). Removed the right rear door trim and inspected the wiring harness at the door hinge. Found the LIN wire (pink-green) had completely fractured inside the corrugated tubing, with only a few copper strands maintaining connection due to metal fatigue from repeated door opening and closing. Repair: Cut out the damaged harness section, soldered with waterproofing, and sealed with heat shrink tubing. Rerouted the wiring with additional slack and secured the harness to prevent excessive bending. Cleared the fault codes and monitored for one month without recurrence.
BYD DTC AI Analysis

Sensor connector corroded and oxidized after water wading

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Vehicle: 2018 Qin Pro (petrol variant) Symptoms: Airbag warning light stayed on constantly the day after driving through heavy floodwater, and the right rear window worked intermittently. Diagnosis: Retrieved DTCs B167E00 and B167D00. Removed the right rear door trim panel and found visible water droplets inside the side impact sensor connector. Terminals showed green corrosion, and resistance between terminals measured 12Ω (abnormal). Solution: Thoroughly cleaned the connector terminals with anhydrous alcohol and electronic contact cleaner, blow-dried them, applied conductive grease, and replaced the connector seal. Also cleared the door drain holes and checked the waterproof membrane seal. Fault eliminated after repair.
BYD DTC AI Analysis

Internal IC thermal stability failure in the sensor

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Vehicle: 2019 Qin Pro DM Symptoms: During summer, when ambient temperature exceeds 35°C, the airbag warning light illuminates intermittently. In the early morning or shaded areas, the light stays off. Diagnosis: When the fault occurred, we pulled DTC B167E00 with no history faults. The fault disappeared after the vehicle cooled for 1 hour. Wiring harness continuity and voltage were normal. However, the LIN bus waveform showed heavy noise when the fault was active. After letting the vehicle bake in direct sunlight for 2 hours, we measured normal power supply at the sensor but no LIN signal output. Solution: Replaced the right rear side impact sensor (part number: 95920-XXXXX). After replacement, we tested the vehicle in high-temperature conditions for three consecutive days, and the fault did not recur. Root cause: poor thermal stability of the sensor's internal communication chip.
BYD DTC AI Analysis

Aftermarket door audio installation damaged the wiring harness

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Model: Qin Pro Fuel 2018 Symptom: The airbag warning light came on after the owner modified the right rear door speaker. Diagnosis: Read DTC B167E00. Inspection found that the mounting screws for the modified speaker had penetrated the door wiring harness protective sleeve, crushing and damaging both the LIN wire and ground wire and causing an intermittent short circuit. Solution: Removed the mounting screws, repaired the damaged wiring harness (re-wrapped with insulation tape and corrugated tubing), and rerouted the harness away from the modified components. Cleared the fault codes and the system returned to normal. Advised the owner to get electrical modifications done at a 4S dealership or professional modification workshop.
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.