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B16FE11

DTC B16FE11 indicates a short to ground in the fourth circuit of the airbag system (SRS) crash sensor — Qin Plus

Safety System

DTC B16FE11 indicates a short to ground in the fourth circuit of the airbag system (SRS) crash sensor.

In the BYD SRS architecture, the "fourth circuit" typically refers to the signal return or diagnostic feedback circuit of the right rear side crash sensor (located in the right C-pillar/rear bumper area).

This circuit abnormally connects to body ground (GND), causing the SRS control unit to detect an abnormal sensor signal voltage (continuous low level) and fail to receive the crash acceleration signal correctly.

This fault triggers the SRS degraded mode, potentially causing complete airbag system failure (non-deployment) or a risk of unintended deployment.

This constitutes a safety-critical fault.

In this DTC, "B" represents the body system, "16F" identifies the SRS subsystem, and "E11" specifically indicates a short to ground in the right rear sensor circuit.

4
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Right C-pillar wiring harness chafed: Prolonged driving on rough roads or underbody bottoming out damages the right rear side impact sensor wiring harness insulation. The copper core contacts the vehicle body metal, creating a short to ground.
  • 2Connector water ingress and oxidation: The right rear crash sensor mounts to the lower C-pillar or inside the rear bumper. Car washing, wading, or poor sealing allows moisture to enter the K05 connector, causing a short circuit between pins or a short to ground.
  • 3Internal sensor fault: A damaged crash sensor integrated circuit causes the fourth signal wire to short to ground internally. This commonly occurs when a minor collision damages the sensor and it remains unreplaced.
  • 4Improper repair work: Failing to reinstall wiring harness retaining clips during accident repairs or interior trim removal and installation (such as the rear quarter panel, C-pillar trim, or rear bumper) pinches the wiring harness in a sheet metal seam and damages the insulation.
  • 5Rodent damage: During extended outdoor parking, rodents chew through the right rear wiring harness sheath, exposing wires and causing contact with the vehicle body (high-voltage electromagnetic fields of new energy vehicles attract rodents).
What To Do
  • 1
    Safe power-down and wait: Disconnect the 12V battery negative terminal and wait at least 3 minutes (5 minutes for some models) to fully discharge the SRS backup power supply and prevent accidental airbag deployment during repair.
  • 2
    Fault confirmation and location: Use a VDS2000/Launch X431 diagnostic tool to read the fault code and confirm B16FE11 is a current fault; consult the wiring diagram to confirm the right rear crash sensor location (Qin EV/E2: below the right C-pillar; E3: on the right rear longitudinal beam).
  • 3
    Visual inspection: Remove the right C-pillar trim panel or rear bumper. Check the wiring harness for wear, damaged insulation, or signs of crushing. Check connectors K05(F)/K05(D) for signs of water ingress, terminal corrosion, or backed-out pins.
  • 4
    Circuit continuity test: Disconnect the SRS control unit and crash sensor. Use a multimeter to measure the resistance to ground of the fourth wire on the sensor side (usually connector pin 2). The normal reading is infinity (OL). A reading of 0-5Ω confirms a short to ground.
  • 5
    Isolate the short circuit in sections: If the circuit shorts to ground, use the split-half method to progressively strip back the wiring harness sheath. Focus on insulation damage where the harness passes through sheet metal holes, at retaining clips, and within 10 cm of the back of the connector.
  • 6
    Connector treatment: If the connector has water ingress, clean thoroughly with electronic cleaner, blow dry with an air gun, and apply conductive grease. If pins are corroded or loose, replace the connector terminals or the entire wiring harness.
  • 7
    Sensor replacement verification: If the wiring harness tests normal, replace the right rear crash sensor (part number varies by model; e.g., Qin EV: K2A-3638460). Clear the fault code, road test the vehicle, and observe if the fault reoccurs.
  • 8
    System reset and verification: Reconnect the battery, turn the ignition ON, and confirm the SRS warning lamp turns off after the self-check. Use a diagnostic tool to read the data stream and confirm the right rear crash sensor acceleration signal is normal (static value: 0±0.5G).
Real-World Cases
BYD DTC AI Analysis

Loose connection at right C-pillar connector triggered SRS warning in BYD Qin EV

✓
2019 BYD Qin EV, 32,000 km. The owner reported that at startup, the instrument cluster displayed "Please check SRS system" and the airbag warning light stayed on. The technician connected a VDS diagnostic tool and retrieved DTC B16FE11: sensor line 4 short to earth. Using the wiring diagram, the technician located the fault at the right C-pillar impact sensor (K05 connector). They removed the right C-pillar trim panel and found abnormal continuity between pins 1 and 2 of the K05(D) connector. Wiggling the connector caused the fault to disappear intermittently. The diagnosis was poor internal pin contact in the connector, causing abnormal impedance to earth on the signal line. Repair: The technician used a dedicated terminal removal tool to extract the terminals, cleaned the oxide layer, and adjusted the contact tension. After reassembly, the fault cleared and the SRS system returned to normal.
Original source ↗
BYD DTC AI Analysis

Short circuit in right rear sensor wiring after BYD E2 drove through water

✓
2020 BYD E2. After driving through flood water during heavy rain, the SRS warning light illuminated on the instrument cluster. The scan tool retrieved DTC B16FE11. Inspected the right rear impact sensor (located inside the right rear longitudinal member) and found connector K05 internally contaminated with muddy water, creating a conductive electrolyte path between the signal wire terminal (pin 4) and the connector housing (ground) with a resistance of only 12Ω. Further inspection revealed damage to the wiring loom corrugated tube, through which water entered. Replaced the right rear impact sensor wiring harness assembly (including connector). Performed a seal test on the sensor body to confirm no internal short circuit. Rewrapped the loom and upgraded the waterproofing (added waterproof tape wrapping). Cleared the DTC, resolving the fault.
BYD DTC AI Analysis

BYD Qin Pro DM wiring harness chafing after accident repairs

✓
2018 Qin Pro DM. After a right rear collision, an independent repair shop replaced the right rear quarter panel. The owner then noticed the SRS warning light illuminating intermittently. Scanning revealed DTC B16FE11 with intermittent status. Inspection found that the right C-pillar wiring harness retaining clip was not installed correctly during the accident repair. While driving, the harness rubbed against the metal edge of the inner quarter panel, damaging the insulation on the fourth signal wire and exposing the copper core. The exposed wire occasionally contacted the body, causing an intermittent short to ground. Solution: Repaired the damaged wiring by stripping back the insulation, soldering an extension wire, and applying double-layer heat shrink insulation. Re-routed the harness to specification and secured the retaining clips, ensuring a minimum 20 mm clearance from sheet metal edges. This completely resolved the fault.
BYD DTC AI Analysis

BYD E3 aftermarket stereo installation caused SRS fault

✓
2020 BYD E3. The day after the owner had a rear subwoofer installed, the instrument cluster displayed an SRS fault. The scan tool retrieved DTC B16FE11. Inspection found the installer routed wiring through the right C-pillar and secured the harness with metal cable ties; the tie edges cut through the protective sheath of the right rear impact sensor harness and caused the fourth wire to short to ground. Worse, the installer connected the modification ground wire to the SRS harness shielding, altering the circuit potential. Solution: Removed the non‑compliant modification wiring, repaired the damaged SRS harness (replaced the section from the right C-pillar to the SRS module), restored the factory ground configuration, and cleared the fault codes. The system returned to normal.
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.