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B16E100

B16E100 is a BYD SRS (Supplemental Restraint System) proprietary fault code indicating an internal circuit fault or abnormal communication signal in the Left Rear Impact Sensor — Atto 3

Safety System

B16E100 is a BYD SRS (Supplemental Restraint System) proprietary fault code indicating an internal circuit fault or abnormal communication signal in the Left Rear Impact Sensor.

This sensor typically mounts in the left rear C-pillar, D-pillar, or inside the rear bumper.

It operates as a piezoelectric or MEMS accelerometer and communicates with the Airbag Control Unit (ACU) via the LIN bus or a hardwired connection.

During this fault, the ACU cannot accurately receive the left rear impact acceleration signal.

This failure may prevent the side curtain airbag and left rear seat belt pretensioner from deploying during a collision.

In extreme cases, the abnormal signal risks unintended airbag deployment.

The following conditions typically trigger this fault code: abnormal sensor supply voltage (below 9V or above 16V), LIN bus communication timeout (no valid data for over 500ms), or internal sensor self-check failure (accelerometer drift or EEPROM checksum error).

The B16E100 fault code on the Atto 3 indicates a medium-severity fault with the left rear impact sensor in the SRS airbag system. The airbag control unit may not receive a valid crash signal, which can affect curtain airbag or seat belt pretensioner operation. Common causes include an internal sensor fault or damaged, corroded, or loose wiring/connectors. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Atto 3
  • 1Internal circuit fault in the sensor body: Piezoelectric element aging, MEMS chip damage, or internal EEPROM data loss prevents normal acceleration signal output or causes self-test failure.
  • 2Wiring harness and connector fault: Loose wiring harness connector at the left rear C-pillar/left side of the luggage compartment, oxidized or backed-out terminals, corrosion from water ingress, or LIN wire short to ground, short to power, or open circuit.
  • 3Installation and mechanical issues: Loose sensor retaining bolts or deformed mounting bracket (common after accident repairs), preventing the sensor from accurately detecting collision acceleration.
  • 4Electromagnetic interference or abnormal voltage: Aftermarket electronic equipment installed on the vehicle causes LIN bus signal interference, or unstable battery voltage or corroded ground points cause abnormal sensor power supply.
  • 5SRS control unit (ACU) fault: Damaged ACU internal sampling circuit or outdated software version causes incorrect interpretation of the left rear impact sensor signal.
What To Do
  • 1
    Diagnostic scan: Use VDS2000/VDS1000 to read the complete fault codes and freeze frame data. Confirm whether B16E100 is a current or history fault. Record the vehicle speed, voltage, and other data from when the fault occurred.
  • 2
    Physical inspection: Remove the left rear C-pillar trim panel or rear bumper. Check the left rear impact sensor for damage or cracks. Verify the installation torque (usually 8-10 N·m) and inspect the bracket for deformation.
  • 3
    Circuit inspection: Disconnect the battery negative terminal, wait 3 minutes, then unplug the sensor connector. Measure the power supply pin (usually 12V), the ground pin (resistance <1Ω), and the LIN line (normal dynamic voltage approx. 7-11V).
  • 4
    Replacement verification: Swap the left and right rear impact sensors, or install a known good sensor. Observe if the fault code transfers to distinguish between a sensor fault and a wiring fault.
  • 5
    Wiring harness inspection: Inspect the wiring harness along the left rear door sill trim and C-pillar for wear, pinching, or signs of water ingress. Focus on contact points between the wiring harness and sharp metal body edges, and check connector sealing.
  • 6
    System reset: After repair, reconnect the battery. Use the diagnostic tool to clear the fault code. Execute the SRS system self-check procedure. Perform a tap test to verify the repair (tap the vehicle body near the sensor with a rubber mallet and observe data stream changes).
Real-World Cases
BYD DTC AI Analysis

Airbag warning light on due to loose connection at left rear C-pillar wiring harness connector in Qin Pro DM.

✓
The instrument cluster intermittently displayed 'Check SRS System'. Scanned DTC B16E100 (left rear collision sensor fault). Inspection found a loose connection in the wiring harness connector behind the left rear C-pillar trim; pins showed slight oxidation. The connector sits near the left rear seat mounting bracket and had worked loose from prolonged driving on rough roads. Cleaned the connector pins with electronic contact cleaner, applied conductive grease, re-secured the wiring harness clips, and fully locked the connector. Cleared the DTC and road tested. SRS system returned to normal operation; fault has not recurred.
Original source ↗
BYD DTC AI Analysis

Water ingress corrosion of left rear impact sensor — Qin PRO petrol variant

✓
After driving through standing water, the airbag warning light remained on. VDS retrieved DTC B16E100. Inspection found the left rear of the vehicle had previously been in a minor rear-end collision. The left rear impact sensor is installed inside the C-pillar. The previous repair did not properly waterproof the wiring harness. Following recent heavy rain, moisture penetrated the C-pillar seal, tracked along the sensor harness into the connector, and caused a short to ground on the LIN line (measured resistance only 2 Ω). Replaced the left rear impact sensor (internal water damage), repaired the damaged section of the harness, re-wrapped the harness with waterproof tape, applied waterproof sealant to the connector, and corrected the C-pillar seal installation.
Original source ↗
BYD DTC AI Analysis

Qin Pro: Wiring harness chafing inside the left rear fender caused sensor communication interruption.

✓
While driving, the instrument cluster suddenly displayed an airbag fault, with the child detection warning light also illuminating. The scan tool retrieved DTC B16E100 and several network communication fault codes. Inspection identified wiring harness interference between the left rear fender liner and body sheet metal. The left rear impact sensor LIN wire insulation had chafed through, causing an intermittent short to ground. The fault originated from improper harness routing during assembly; repeated trunk operation over time had caused the harness to rub against sharp sheet metal edges. Repaired the damaged harness (single LIN wire), protected it with corrugated tubing, rerouted the harness to clear sharp edges, and re-secured the cable ties. Cleared the DTCs, performed repeated trunk opening tests and a road test; fault resolved.
Original source ↗
BYD DTC AI Analysis

Qin PRO DM left rear impact sensor accelerometer drift fault

✓
No accident history. Airbag warning light on instrument cluster illuminated intermittently. DTC B16E100 appeared intermittently. Checked wiring harness and connectors; all normal. Supply voltage 12.4V. LIN bus waveform normal. Used diagnostic tool to read sensor real-time data stream. Found left rear impact sensor stationary baseline acceleration value deviated significantly from right rear sensor (X-axis offset 0.8G, normal <0.3G). Diagnosis: internal MEMS chip aging drift. Replaced left rear impact sensor. After replacement, performed sensor zero-point calibration (accessed SRS special functions via VDS). Cleared fault codes and conducted static and dynamic tests. Data stream returned to normal range.
Other Atto 3 Fault Codes
P0AA6Hybrid Battery Voltage System Isolation FaultB1108For 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.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.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.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.
Common problems reported for Atto 3 →Atto 3 overview →
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.