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B165E11

DTC B165E11 indicates the SRS (Supplemental Restraint System) control unit detects an abnormally low-resistance path (typically <1Ω) between the right front impact sensor signal or power circuit and body ground, constituting a short to ground — Seal U

Safety System

DTC B165E11 indicates the SRS (Supplemental Restraint System) control unit detects an abnormally low-resistance path (typically <1Ω) between the right front impact sensor signal or power circuit and body ground, constituting a short to ground.

In BYD E2/E3/Qin EV architectures, this sensor utilizes a bipolar MEMS accelerometer and communicates with the SRS ECU via a hardwire or LIN bus connection.

A short to ground causes the ECU to continuously receive a 0V reference signal, preventing it from distinguishing between "no collision" and "circuit fault" states.

Per ISO 26262 functional safety requirements, the system enters Fail-Safe mode: it immediately illuminates the airbag fault warning lamp and disables right front airbag and side curtain airbag deployment to prevent unintended triggering or failure to deploy.

This represents a severe ASIL-D fault.

4
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Internal short circuit in the sensor body: Overvoltage, static electricity, or aging causes a breakdown between the power supply pin and ground of the right front crash sensor integrated circuit (ASIC). This commonly occurs after vehicle wading or a battery system insulation fault.
  • 2Wiring harness mechanical damage: Front bumper removal/installation, accident repairs, or over-tightened fender liner retaining clips abrade the sensor wiring harness insulation (usually located on the outer side of the right front longitudinal beam), causing the copper core to directly contact the vehicle body metal frame.
  • 3Connector water ingress and corrosion: The sealing ring on the wiring harness connector inside the right front bumper (usually located behind the headlamp or on the right side of the radiator support) degrades. This allows water to accumulate inside after washing the vehicle or driving through water, causing an electrolytic short to ground between the pins.
  • 4SRS ECU internal monitoring circuit fault: Abnormal ground reference point in the control unit A/D sampling circuit causes the ECU to misidentify normal sensors as short circuits (rule out using the cross-check method).
  • 5Interference from modifications or external devices: Drawing power for unauthorized aftermarket front radars, dash cams, or similar equipment accidentally damages the SRS wiring harness, or using unshielded wiring introduces a ground loop.
What To Do
  • 1
    Safe power-down and discharge: Switch off the ignition, disconnect the low-voltage battery negative terminal, wait at least 90 seconds (to fully discharge the SRS energy storage capacitor), and wear an anti-static wrist strap.
  • 2
    Initial visual inspection: Remove the right front bumper cover. Inspect the right front crash sensor (located at the front of the right front longitudinal beam or below the headlamp bracket) for physical damage or cracks. Inspect the wiring harness corrugated conduit for wear or crush marks. Check the connector for looseness or signs of water ingress (white powder or verdigris).
  • 3
    Static measurement verification: Disconnect the sensor connector. Use a multimeter to measure the resistance between the harness-side signal pin (usually the yellow/green wire) and body ground. The normal value is >10 MΩ (open circuit); a reading of <5 Ω confirms a short to ground. Simultaneously measure the voltage between the power supply pin (usually the orange wire) and ground to verify no abnormal voltage is present.
  • 4
    Sensor body test: Measure the resistance between each terminal of the removed crash sensor. The normal value is 2.0-4.0 kΩ (refer to the workshop manual standard values). If the reading is <100 Ω or any terminal has continuity with the sensor housing, replace the sensor.
  • 5
    Section-by-section wiring harness inspection: If the sensor is normal, strip the wiring harness sheath in sections from the sensor end toward the SRS ECU (usually located under the center console or behind the armrest box). Closely inspect the harness at the fender liner bend and near the front longitudinal beam weld points. Locate any damaged insulation and repair using heat-shrink tubing or tape.
  • 6
    ECU cross-check: Swap the left and right front impact sensors. If the fault code follows the sensor to the left side (changes to B165D11), the sensor is faulty. If the fault code remains on the right side, check the wiring harness or ECU.
  • 7
    Repair and Replacement: Replace the faulty sensor (part number must match the vehicle model, e.g., E2-53420XXX) or repair the wiring harness and wrap it with waterproof tape. Verify the connector sealing ring is intact.
  • 8
    System reset and verification: Reconnect the power supply. Use the VDS2000 or BYD dedicated diagnostic tool to clear the fault code. Perform the 'SRS system self-check' (takes about 30 seconds) and confirm B165E11 does not recur. Read the right front crash sensor data stream. Lightly tap the longitudinal beam near the sensor and observe the acceleration value changes (should fluctuate within 0-50mV). Confirm normal system operation.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

E2 SRS light on after water ingress: right front impact sensor connector shorted due to water entry

✓
2019 BYD E2. The owner reported the airbag warning light stayed on after driving in heavy rain. Retrieved DTC B165E11. Inspection found visible water droplets inside the right front bumper sensor connector; the pins were green with oxidation. Cause: the connector seal ring had aged, letting water in when wading and shorting the power pin to ground. Repair: cleaned the connector pins, applied electronic contact cleaner, and replaced the waterproof seal ring. Fault resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

Intermittent B165E11 on Qin EV after accident repair: bumper clip pinched wiring harness

✓
2020 BYD Qin EV. After right-front collision repair, the SRS warning light illuminated intermittently while driving. The scan tool showed stored fault code B165E11. Inspection found that fender liner clips re-secured during the repair pressed directly on the wiring harness. When driving over bumps, the harness insulation chafed through, allowing copper wires to contact the body. Repair: Rerouted the harness, secured it with dedicated clips, and repaired the damaged insulation with double-layer heat shrink tubing. Fault cleared.
BYD DTC AI AnalysisFrom Chinese market (translated)

E3 radar modification caused SRS system false alarm: wire splicing caused short circuit

✓
2020 E3. Owner had front parking sensors fitted at a non-authorised workshop; the next day, the airbag warning light came on immediately at startup with fault code B165E11. Inspection found the installer had cut into the SRS wiring harness (yellow corrugated tubing) at the right front side member to tap power, damaging the signal wire insulation and creating a short to earth. Repair: removed the illegal wiring taps, repaired the SRS harness (required replacing the complete section to ensure impedance matching), and returned the vehicle to factory condition. Fault cleared.
BYD DTC AI AnalysisFrom Chinese market (translated)

Sensor-internal ASIC breakdown: hard short caused by aging

✓
2019 Qin EV, 80,000 km, no accident or water immersion history. DTC B165E11 appeared suddenly. Measured resistance between sensor power pin and ground: only 0.3 Ω. This confirmed the internal voltage regulator had shorted. Cause: long-term operation in the engine bay’s high temperatures aged the internal capacitor, causing a power-to-ground short. Fix: replaced the right front impact sensor (part number SC-3636100), performed sensor calibration, and the system returned to normal.
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]