AU
B16FB11

DTC B16FB11 indicates abnormal continuity between the Supplemental Restraint System (SRS) crash sensor (or pressure sensor) signal circuit (the third wire, typically the SIG signal wire) and body ground — Qin Plus

Safety System

DTC B16FB11 indicates abnormal continuity between the Supplemental Restraint System (SRS) crash sensor (or pressure sensor) signal circuit (the third wire, typically the SIG signal wire) and body ground.

In the BYD SRS circuit architecture, the front crash sensor typically uses a three-wire system: power supply (+B), ground (GND), and signal (SIG).

When the signal wire shorts to ground, the SRS ECU detects a continuous 0V (or near 0V) signal.

This contradicts the pulse signal or specific voltage value present during normal operation, causing the ECU to determine a sensor circuit fault.

This fault forces the airbag system into fail-safe mode and continuously illuminates the airbag warning lamp.

In a collision, the airbags may fail to deploy or deploy unintentionally, posing a severe safety hazard.

4
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Vehicle vibration, aging, or prolonged friction against metal edges damages the crash sensor wiring harness insulation in the front longitudinal beam or front bumper, causing the signal wire core to short to body ground.
  • 2Water enters the sensor connector (usually located inside the front fender liner or front bumper) when driving through water or washing the vehicle, causing a short circuit between terminals or between a terminal and the connector housing (ground).
  • 3Improperly secured wiring harness after accident repairs. Clips, cable ties, or metal brackets pinch the harness, damaging the internal wire insulation and causing a short to ground.
  • 4Crash sensor internal circuit fault. Signal processing IC or current-limiting resistor breakdown causes the signal line to short internally to ground.
  • 5Rats or other small animals chewed the engine compartment wiring harness, damaging the sensor harness and causing it to contact vehicle body metal.
What To Do
  • 1
    Use a BYD dedicated diagnostic tool (VDS or ED400) to read freeze frame data, confirm the specific faulted sensor location (left front crash sensor, right front crash sensor, or center sensor), and record the vehicle status at the time of the fault.
  • 2
    Perform the SRS system safety procedure: turn the ignition switch to the OFF position, disconnect the battery negative terminal, and wait at least 90 seconds to fully discharge the backup power supply and prevent accidental airbag deployment.
  • 3
    Remove the front bumper or fender liner at the location corresponding to the fault code. Visually inspect the crash sensor connector and wiring harness. Check the wiring harness corrugated conduit for wear, cuts, or signs of water ingress. Inspect the connector pins for corrosion, deformation, or push-back.
  • 4
    Disconnect the sensor connector and use a multimeter to measure the resistance between pin 3 on the harness side (signal wire, usually yellow or white) and body ground. The normal value should be greater than 1 MΩ (infinity). If the resistance is less than 1 Ω, a short to ground exists. If the resistance is between 1 and 1000 Ω, check for an intermittent or high-resistance short.
  • 5
    Inspect the wiring harness along its routing, paying special attention to metal edges at the front side member, radiator support, and headlamp bracket. If damaged, repair the insulation using heat-shrink tubing or electrical tape. Replace the entire harness section if necessary. If the harness is intact, measure the resistance between sensor-side pin 3 and the housing. If continuity exists, replace the crash sensor.
  • 6
    After completing the repair, reconnect all connectors, connect the battery negative terminal, and turn the ignition switch to the ON position. Use the diagnostic tool to clear the fault code and perform the SRS system self-check (allow about 30 seconds for the system to complete the pre-check cycle).
  • 7
    Perform a road test, simulating rough road conditions, to confirm the fault code does not reappear. Verify the instrument cluster airbag warning light turns off normally after the self-check. Read the data stream to confirm the sensor signal voltage is within the normal range (typically around 2.5V or according to the specific communication protocol values for the vehicle model).
Real-World Cases
BYD DTC AI Analysis

Qin Pro DM: SRS warning light on after wading

✓
A 2019 Qin Pro DM's airbag warning light stayed on constantly after driving through heavy rain and flood water. The scan tool retrieved code B16FB11 (right front impact sensor line 3 short to ground). We removed the right front bumper and found the right front impact sensor mounted on the inner side of the front longitudinal member. The connector seal had aged, letting water enter the connector when wading through water and creating an electrolytic conductive path between the signal terminal and the connector housing (ground). We cleaned and dried the connector, replaced the seal, and applied electrical contact protector inside the connector, fixing the fault. We recommend checking the connector waterproofing on other vehicles from the same production batch.
BYD DTC AI Analysis

BYD E2: Airbag warning light comes on intermittently while driving

✓
2020 BYD E2: The airbag warning light intermittently illuminates when driving on rough surfaces, extinguishing after an ignition restart. The scan tool retrieved history DTC B16FB11 (left front sensor short to earth). Inspection found the left front impact sensor wiring harness chafing where it passes through the front fender reinforcement beam aperture. A missing rubber grommet allowed the harness to chafe against the metal edge, wearing through the insulation on the third signal wire and causing intermittent contact with the body during vibration. Repair: Re-soldered the damaged wire and insulated it with heat shrink tubing, fitted a rubber grommet and foam wrapping where the harness passes through the sheet metal, and rerouted the harness to eliminate stress points. Fault permanently resolved.
BYD DTC AI Analysis

Qin EV unable to clear DTCs after accident repair

✓
This 2019 BYD Qin EV suffered a front collision. After the workshop replaced the front bumper and left front impact sensor, DTC B16FB11 would not clear. The technician fitted a new sensor but the fault remained. Inspection found the wiring harness was not secured correctly during the accident repair. The newly installed harness was cable-tied to the sharp edge of a metal bracket on the front side member and was pinched during installation. This caused the internal copper conductor of the third signal wire to short to ground. Repair: Rerouted the harness, secured it with dedicated harness clips away from metal edges, and repaired the damaged wire insulation. DTC cleared successfully, SRS system returned to normal.
BYD DTC AI Analysis

BYD E3 reports sensor short circuit after long-term parking

✓
A 2020 BYD E3 sat in an underground garage for two months. On startup, the airbag warning light stayed on, logging DTC B16FB11. Inspection found rodent activity in the engine bay. Rats had chewed on the right front impact sensor wiring harness, exposing the third signal wire, which was touching the metal body. The sensor’s low mounting position near the lower radiator crossmember gives rodents an easy path. Technicians cut out the damaged harness section and reconnected the wires. They wrapped the harness with capsaicin-coated anti-rodent tape, repositioned the sensor, and installed a metal protective plate. Clearing the fault code restored normal operation. Technicians advised the owner to install an engine bay rodent mesh.
Other Qin Plus 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.