AU
B16EF

DTC B16EF indicates the SRS (Supplemental Restraint System) control module detects a communication interruption or missing physical connection with the Right Rear Impact Sensor — Atto 8

Safety System

DTC B16EF indicates the SRS (Supplemental Restraint System) control module detects a communication interruption or missing physical connection with the Right Rear Impact Sensor.

This sensor typically mounts in the right C-pillar, rear door frame, or inside the right rear quarter panel to monitor collision acceleration changes on the right rear side of the vehicle.

During a side-rear collision, the sensor transmits the acceleration signal to the SRS module to determine whether to deploy the right curtain and side airbags.

A "not connected" fault means the SRS module cannot detect the sensor during initialization or periodic communication checks.

Causes include an open circuit, disconnected connector, internal sensor open circuit, or abnormal module power supply.

This fault disables the right rear collision protection function.

As a safety-critical fault, it requires immediate repair.

The B16EF fault code on the Atto 8 indicates the SRS module cannot communicate with, or detect, the right rear impact sensor. This is a medium-severity safety fault that may disable right rear side or curtain airbag protection. Common causes include a loose sensor connector, backed-out terminal, or damaged wiring in the right rear sill or C-pillar area. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
3
Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Sensor harness connector loose, terminal backed out, or poor contact: Commonly caused by failing to fully seat the connector after accident repairs, or prolonged rough road vibration loosening the retaining clip.
  • 2Wiring harness open or short circuit: The wiring harness in the right rear sill and C-pillar area breaks after vehicle wading, accidents, prolonged bending, or rodent damage. Metal edge chafing causes a short to ground or power.
  • 3Internal sensor fault: Damage to the sensor's internal piezoelectric element or processing circuit causes no signal output or a power supply short circuit.
  • 4SRS control module power supply or communication fault: An abnormal module IGN power supply or ground circuit, or a CAN bus communication circuit fault, prevents sensor recognition.
  • 5Sensor installation/configuration error: Failed to write the configuration code (VIN matching or sensor position learning) after replacing the sensor, or installed a sensor with an incorrect part number.
What To Do
  • 1
    Safety preparation and fault confirmation: Disconnect the negative battery terminal and wait at least 90 seconds to fully discharge the SRS capacitor. Use VDS2000 or a BYD dedicated diagnostic tool to read fault codes. Confirm B16EF is a current fault (ACTIVE), not a historical fault. Verify the 'Right Rear Impact Sensor Status' in the data stream shows 'Not Connected' or 'Communication Failure'.
  • 2
    Physical connection check: Remove the right C-pillar interior trim panel or rear door sill trim panel and locate the right rear impact sensor (typically a yellow connector). Verify the connector is fully seated, the locking tab is intact, and the terminals are not backed out or corroded. Inspect the sensor mounting bracket for deformation or looseness.
  • 3
    Harness continuity and voltage measurement: Disconnect the sensor and SRS module connectors. Measure the wiring harness end-to-end continuity (should be less than 1 Ω). Measure the power wire voltage to ground (should be 12 V battery voltage). Measure the ground wire resistance to ground (should be less than 1 Ω). Check the signal wire for a short circuit to power or ground.
  • 4
    Sensor inspection: If the wiring harness is normal, measure the sensor resistance (refer to the workshop manual; typically several kΩ to tens of kΩ, depending on the specific model). If the resistance is infinite or zero, replace the sensor. Inspect the sensor exterior for physical cracks or signs of water ingress.
  • 5
    Replacement and restoration: After installing a new sensor or repairing the wiring harness, listen for a 'click' to confirm the connector latch locks. Reconnect the battery, use the diagnostic tool to clear the fault code, and perform an 'SRS system self-check' or 'crash sensor configuration' (some models require writing a configuration code or performing sensor position learning).
  • 6
    Verification test: Start the vehicle and confirm the SRS warning light turns off; read the data stream and confirm the sensor status displays 'Normal'; perform a tap test (lightly tap the sensor mounting area and observe the data stream for changes in the acceleration value) to confirm system function has returned to normal.
Real-World Cases
BYD DTC AI Analysis

BYD Tang DM: Backed-out pin in right rear collision sensor connector causing intermittent fault

✓
The SRS warning light occasionally came on while driving and turned off after restarting. A VDS scan showed intermittent DTC B16EF. Inspected and found the sensor connector inside the right C-pillar trim was plugged in, but the terminals had backed out due to a previous improper repair, causing poor contact when driving over bumps. Re-crimped the terminals, applied conductive paste, and locked the connector fully. The fault has not reappeared.
Original source ↗
BYD DTC AI Analysis

BYD Song MAX: Open circuit in right rear impact sensor wiring harness after accident repair

✓
The vehicle had a right rear side scrape. After repairs at a workshop, the SRS warning light stayed on. Diagnosis showed current fault B16EF. Inspection revealed the accident had crushed and severed the wiring harness inside the right rear sill, breaking both power and signal wires. Repaired the harness by soldering and sealing with heat shrink tubing, rerouted the wiring to prevent chafing against metal edges, and cleared the fault codes. System returned to normal.
Original source ↗
BYD DTC AI Analysis

BYD Yuan EV right rear impact sensor internal short circuit after wading

✓
After water fording, the SRS warning light came on with DTC B16EF. Inspection revealed poor sealing of the right rear fender liner, letting water seep into the sensor mounting hole and causing a short circuit that damaged the sensor internally. Replaced the right rear impact sensor, cleaned corrosion and water ingress on the harness connector, and renewed the waterproof seal using a rubber gasket. Fault resolved.
Original source ↗
Other Atto 8 Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.