AU
B16E7-00

DTC B16E7-00 indicates the airbag system (SRS) detected a communication interruption or abnormal signal between the Middle Rear Impact Sensor and the SRS control module — Atto 3

Safety System

DTC B16E7-00 indicates the airbag system (SRS) detected a communication interruption or abnormal signal between the Middle Rear Impact Sensor and the SRS control module.

This sensor typically mounts on a structural member in the middle rear of the vehicle (such as the lower C-pillar or rear panel crossmember) and monitors collision acceleration in the middle rear area.

The SRS module sets this DTC if it fails to receive a valid signal from the sensor within the specified time, or if it detects an open or short circuit in the wiring.

This fault may prevent the side curtain airbags, rear side airbags, or seat belt pretensioners from deploying correctly during a middle rear collision.

This severely compromises passive safety protection and continuously illuminates the instrument panel airbag warning light.

4
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Sensor wiring harness connector loose, oxidised, or subject to water ingress: Due to the low mounting position of the centre rear impact sensor (typically on both sides of the boot or behind the rear seats), car washing, wading, or damp environments easily oxidise and corrode the connector pins, causing excessive contact resistance or signal interruption.
  • 2Crash sensor internal fault: A damaged internal accelerometer or processing chip fails to generate a valid crash signal or causes abnormal CAN/LIN bus communication.
  • 3Wiring harness open or short circuit: Incorrect harness connection after rear collision repair, or chafing or rodent damage during long-term use, causing power, ground, or signal wire faults.
  • 4SRS control unit (ACU) interface fault: Damage to the interface circuit for the corresponding sensor inside the airbag control module prevents correct interpretation of the sensor signal.
  • 5Sensor mounting bracket deformed: Minor rear-end impact deforms the sensor mounting base, causing insecure sensor mounting or altering its orientation, triggering the internal fault monitoring circuit.
What To Do
  • 1
    Use the VDS2000 or BYD dedicated diagnostic tool to read the complete fault codes and freeze frame data. Confirm if the fault is current (Active) and record the vehicle status when the fault occurred. Check if other related crash sensor fault codes are also present.
  • 2
    Locate the center rear impact sensor (on Qin series models, this is usually located in the upper middle area behind the rear seat backrest or inside the C-pillar trim panel). Remove the corresponding trim panel and visually inspect the sensor for impact marks, cracks, or water stains. Verify the connector is fully seated and the retaining clip is not broken.
  • 3
    Disconnect the battery negative terminal and wait 3 minutes (safety procedure). Unplug the sensor connector and use a multimeter to measure the harness-side terminals: check the supply voltage (typically 12V or 5V; refer to the circuit diagram), ground wire continuity (resistance must be less than 1Ω), and signal wire insulation to ground/power. Also measure the resistance between the sensor-side connector pins to check for an internal sensor short circuit.
  • 4
    Inspect the wiring harness routing. Specifically check the harness passing through the tailgate hinge and rear seat mounting points for wear, breaks, or crushing by foreign objects. If available, use an oscilloscope to test the signal waveform for interference or distortion.
  • 5
    If the wiring harness measurements are normal, replace the center rear impact sensor (verify the part number against the vehicle configuration, distinguishing between high-spec and low-spec sensor models). Install the sensor in the correct direction (the arrow on the sensor surface usually points toward the front of the vehicle) and tighten to the specified torque (usually 8-10Nm).
  • 6
    Reconnect all components and the battery negative terminal. Clear the fault code using the diagnostic tool and perform the SRS system self-check (usually requires cycling the ignition switch three times or executing a specific diagnostic procedure). Confirm DTC B16E7-00 does not return and the airbag warning lamp turns off. Perform a simulated crash test (using the diagnostic tool to run the sensor test function) to verify the sensor data stream is normal.
Real-World Cases
BYD DTC AI Analysis

Centre rear collision sensor connector oxidised after driving through water

✓
The owner of a 2017 BYD Qin EV300 reported the airbag warning light stayed on after washing the car. The scan tool showed fault code B16E7-00 (current fault). We removed the left boot trim panel and found obvious water stains inside the center rear impact sensor connector, with the pins showing green oxidation. The boot seal had deteriorated, allowing high-pressure wash water to seep into the C-pillar area. We cleaned the connector pins with electronic cleaner, applied conductive grease to prevent corrosion, replaced the seal, and resolved the fault.
BYD DTC AI Analysis

Loose wiring harness connection after accident repair caused the fault

✓
2018 BYD Qin EV450. One week after rear-end collision repair, the instrument cluster showed an airbag fault. Scanned DTC B16E7-00. Inspection found that during the repair, the technician removed the rear bumper and rear panel, but when reinstalling did not fully insert the mid-rear impact sensor harness connector, leaving it half-plugged. Vibration from driving caused poor contact. Firmly reconnected the connector, secured it with waterproof tape, cleared the fault code, and the system returned to normal.
BYD DTC AI Analysis

Sensor internal circuit aging failure.

✓
A 2017 Qin 100 with 120,000 km developed an intermittent airbag warning light, with DTC B16E7-00 appearing intermittently. Inspected the wiring harness and connectors – all normal. Measured sensor supply and ground – normal. Replaced the centre rear impact sensor and the fault disappeared completely. Disassembled the old sensor and found the internal capacitor had leaked electrolyte, causing unstable accelerometer signal output. This is a common aging failure in sensors from early Qin production batches.
BYD DTC AI Analysis

Aftermarket parking sensor installation damaged the wiring harness

✓
While installing reversing sensors in the boot, the owner drilled too close to the centre rear impact sensor harness route. The drill bit cut into the harness, partially breaking the internal copper wires without completely severing them, causing an intermittent open circuit. This set DTC B16E7-00 sporadically. Repaired the damaged harness using heat-shrink tubing for insulation, and rerouted the reversing sensor wiring away from the factory harness.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For 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.
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.