AU
B16E011

This DTC indicates an abnormally low-resistance connection (short circuit) between the signal circuit of the left rear side impact sensor (SIS) in the Supplemental Restraint System (SRS) and the vehicle body ground (GND) — Seal U

Safety System

This DTC indicates an abnormally low-resistance connection (short circuit) between the signal circuit of the left rear side impact sensor (SIS) in the Supplemental Restraint System (SRS) and the vehicle body ground (GND).

Under normal operating conditions, the impact sensor sends a specific voltage signal (typically a PWM or resistor divider signal) to the SRS control unit (ACU) to indicate its status.

When a short to ground occurs, the ACU detects the circuit voltage remaining at or near 0V and a resistance well below the standard range (typically <1Ω), identifying a short-to-ground fault.

This fault causes the SRS to enter fail-safe mode.

The system illuminates the airbag fault warning lamp and disables the left rear side airbag and curtain airbag deployment functions to prevent accidental deployment caused by the short circuit.

In a severe side-impact collision, the affected airbags may fail to deploy normally, posing a major safety hazard.

3
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Worn or damaged insulation on the left rear crash sensor wiring harness causes the wire to short against the metal vehicle body (commonly where the harness passes sharp edges or retaining clips inside the sill trim panel).
  • 2Seal failure of the internal electronic components within the crash sensor body allows moisture intrusion, causing the printed circuit board (PCB) to short to ground.
  • 3Water ingress, corrosion, or bent pins in the sensor connector (usually located near the C-pillar or rear seat) causing a short circuit between the signal terminal and the ground terminal.
  • 4A rear-end collision damaged the wiring harness without completely severing it. Improper insulation during repair caused a hidden short to ground.
  • 5Internal fault in the SRS control unit (ACU) signal processing circuit causing incorrect sensor signal interpretation (less common; confirm only after ruling out wiring harness issues).
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 and prevent accidental airbag deployment.
  • 2
    Visual inspection: Remove the left rear sill trim panel and lower C-pillar trim panel. Inspect the crash sensor (usually located behind the C-pillar trim panel or near the left rear longitudinal beam) and wiring harness for obvious damage, crushing, or water ingress.
  • 3
    Connector inspection: Disconnect the left rear crash sensor connector and check the terminals for corrosion, deformation, or water ingress. Measure the resistance between the harness-side signal pin and ground. The resistance must be greater than 10kΩ (infinite). If the resistance is too low, the wiring harness is shorted to ground.
  • 4
    Harness circuit inspection: Use a multimeter to measure harness continuity and insulation to ground between the sensor and the ACU. Check the insulation integrity, focusing on areas where the harness passes through body panel holes and at retaining clips.
  • 5
    Sensor inspection: Measure the resistance between the collision sensor signal terminal and the ground terminal (refer to the workshop manual for standard values; normal resistance falls within a specified range, and a short circuit reads close to 0Ω). If abnormal, replace the sensor.
  • 6
    Repair or replace: Repair the damaged wiring harness (use heat-shrink tubing or replace the harness section) or replace the left rear crash sensor assembly. Verify the installation torque meets the standard (typically 8-10 N·m).
  • 7
    System reset: Reconnect the battery, use the VDS2000/3000 diagnostic tool to clear the fault code, and perform an SRS system self-check. Confirm B16E011 does not return and the instrument cluster airbag light turns off.
Real-World Cases
BYD DTC AI Analysis

Water ingress into the left rear impact sensor connector caused a short to ground on the BYD Qin EV.

✓
After wading, the airbag warning light came on the instrument cluster. Retrieved DTC B16E011. Found the left rear impact sensor connector seal below the C-pillar had deteriorated, allowing water ingress that shorted the signal terminal to ground. Drained the connector, applied conductive anti-corrosion compound, and replaced the seal. Fault cleared.
Original source ↗
BYD DTC AI Analysis

Damaged wiring harness insulation after accident repair caused an intermittent short circuit in a BYD E2.

✓
The left rear of the vehicle previously sustained minor collision damage. After repairs at an independent workshop, DTC B16E011 appeared intermittently. Inspection found the wiring harness at the left rear chassis rail poorly secured and chafing against a metal bracket, wearing through the insulation and causing intermittent short-to-earth faults on bumpy roads. Rewrapping the harness and adjusting its mounting position permanently resolved the fault.
Original source ↗
BYD DTC AI Analysis

BYD E3 left rear collision sensor internal PCB short circuit fault

✓
No accident history. After driving in rain, the airbag warning light illuminated constantly with DTC B16E011. Inspected wiring harness — no damage. Measured resistance from sensor connector harness side to ground — normal. Determined internal electronic component seal failure in the sensor caused a short circuit. Replaced left rear impact sensor and performed system calibration. Fault cleared.
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.