AU
B16F0

This DTC indicates an abnormally low-resistance connection between the Supplemental Restraint System (SRS) Right Rear Impact Sensor signal circuit and body ground — Atto 8

Safety System

This DTC indicates an abnormally low-resistance connection between the Supplemental Restraint System (SRS) Right Rear Impact Sensor signal circuit and body ground.

In the BYD SRS architecture, impact sensors utilize a dual-axis accelerometer design, transmitting a 0-5V analog voltage signal to the Airbag Control Unit (ACU) via hardwire.

A short to ground continuously pulls the signal line voltage down to <0.5V (normal static voltage is approximately 2.5V).

The ACU sampling circuit detects this abnormal voltage level and triggers the DTC.

This fault forces the SRS into fail-safe mode, disabling the right rear side airbag and curtain airbag deployment while illuminating the airbag warning lamp.

Because the short circuit can occur anywhere in the wiring harness, excessive short-circuit current (>2A) risks burning out the internal ACU drive circuit.

This single-point failure directly compromises the vehicle's side-rear collision detection capability and, in extreme cases, prevents airbag deployment during a collision.

The B16F0 fault code on the Atto 8 indicates a short to ground in the SRS right rear impact sensor signal circuit. This is a high-severity airbag fault that can disable right rear side and curtain airbag deployment. Common causes include worn wiring near the C-pillar or rear seat bracket, or water-corroded sensor connector pins. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Long-term vibration at the C-pillar or rear seat mounting bracket wears the right rear impact sensor wiring harness. Damaged insulation causes the signal wire to contact the body ground. This is common on vehicles with >50,000 km.
  • 2An aged sealing ring or loose retaining clip on the sensor connector (usually located inside the right rear quarter panel) allows water ingress after washing the vehicle or driving through water, causing electrolytic corrosion between the pins and creating a short-to-ground path.
  • 3External impact or electrical overstress typically causes internal breakdown of the crash sensor ASIC chip, creating an internal short circuit between the signal output terminal and the metal housing (ground).
  • 4During rear accident repairs, improper wiring harness routing allows trim panel clips to crush the harness, or metal clamps to cut through the harness insulation, causing a hidden short circuit.
  • 5A damaged ADC channel in the SRS control unit (ACU) internal sampling circuit or reference voltage drift falsely reports a sensor short to ground (rule out through cross-checking).
What To Do
  • 1
    Use VDS2000 or a BYD dedicated diagnostic tool to read fault codes. Confirm B16F0 is a Current DTC, not a history fault. Record environmental parameters from the freeze frame data, such as vehicle speed and temperature.
  • 2
    Perform the safe power-down procedure: Disconnect the 12V battery negative terminal and wait at least 90 seconds for the SRS capacitor to fully discharge. Do not operate any electrical equipment during this time.
  • 3
    Remove the right rear C-pillar trim panel and rear seat side trim panel. Locate the right rear impact sensor (usually marked 'SIS RR' or 'SENSOR, SIDE IMPACT REAR RIGHT'). Verify the part number is a BYD-specific component (such as the 5A-XXXXXX series).
  • 4
    Visual inspection: Check the sensor body for physical damage. Inspect the connector for obvious signs of water ingress (white powdery corrosion) and bent or backed-out pins. Check the wiring harness corrugated conduit for damage where it passes through the body panel hole.
  • 5
    Disconnect the sensor connector. Use a digital multimeter to measure the resistance between the sensor-side signal pin (usually Pin 2) and the sensor housing. Normal resistance is an open circuit (>10MΩ). If continuity exists (<1Ω), replace the sensor assembly.
  • 6
    Measure the insulation resistance between the harness-side signal wire and ground: must be >1 MΩ. If the resistance is too low, use the half-split method along the harness routing to isolate the fault. Specifically inspect the harness protective sleeve for wear-through at the floor crossmember and seat slide rail mounting points.
  • 7
    If wiring harness insulation is normal, measure the voltage at the sensor signal pin on the ACU side with the ignition ON. The voltage must be the 5V reference voltage (±0.25V tolerance). If the voltage is 0V, the ACU may have an internal short circuit. Measure the resistance between this pin and ground to confirm.
  • 8
    When repairing the wiring harness, double-wrap it with high-temperature tape (125°C grade) and install a rubber grommet at the pass-through hole. When replacing the sensor, apply the standard installation torque (usually 8-10 N·m) and seat the sensor tightly against the vehicle body metal surface to accurately transmit vibration.
  • 9
    Reconnect all connectors (confirm the locking 'click'), reinstall the trim panel, connect the battery, use the diagnostic tool to clear the fault code, and perform the 'SRS system self-check' procedure.
  • 10
    Perform functional verification: Access the data stream to read the 'right rear impact sensor status'. Lightly tap the right rear quarter panel with a rubber mallet to simulate collision vibration. Confirm the sensor output voltage changes accordingly (2.5V→0V or 5V pulse) and the diagnostic tool generates no new fault codes.
Real-World Cases
BYD DTC AI Analysis

Corroded sensor connector on water-wading vehicle caused short circuit

✓
A 2019 BYD Yuan EV with 42,000 km on the clock came in with the airbag warning light permanently on. Scanning revealed current fault code B16F0. Inspection found visible water staining inside the connector of the right rear impact sensor, located at the lower C-pillar. Pins 1 (earth) and 2 (signal) showed green copper corrosion, and resistance between them measured only 0.3 Ω. Investigation traced the cause to the vehicle wading through water deeper than the door sill one month earlier, allowing water to seep in through the wiring harness grommet. Replaced the sensor (internally corroded), cleaned the connector with electronic contact cleaner, fitted a new waterproof seal, and applied waterproof sealant to the sensor mounting base. This cleared the fault. Advised the owner to check the sealing condition of other low-mounted sensors.
BYD DTC AI Analysis

Wiring harness pinched after accident repairs, causing intermittent short

✓
A 2021 BYD Tang developed a B16F0 DTC one week after an accident repair to the left rear quarter panel. Service history showed the left rear wing had been replaced. Investigation revealed that technicians had incorrectly routed the right rear impact sensor wiring harness (which runs parallel to the left rear side harness) beneath the seat mounting bracket. The metal bracket edge cut through the corrugated tubing and crushed the wire insulation, causing the signal wire to short to ground against the bracket. The pinch point was concealed inside the seat rail, making it hard to catch during a routine visual inspection. Repair steps: Released the seat mounting bolts, removed the damaged harness, cut out the damaged section (approximately 15 cm), fused in replacement wiring by soldering (twist connections prohibited), insulated with double-layer heat shrink tubing, and rerouted the harness away from sharp metal edges. The fault was completely resolved.
BYD DTC AI Analysis

Thermal breakdown of the sensor's internal ASIC chip

✓
2019 BYD Song MAX, 68,000 km. Intermittent airbag warning light, DTC B16F0 (intermittent). Initial inspection: wiring harness insulation normal, connectors normal. Used an oscilloscope to monitor the sensor signal line; found intermittent short-to-ground pulses on rough roads. Disassembled the sensor; found slight burn marks on the bottom of the MEMS accelerometer chip on the internal PCB. Determined that long-term high-temperature exposure (sensor mounted on C-pillar metal panel; summer cabin temperatures exceed 70°C) caused breakdown of the chip's internal signal conditioning circuit. Repair: Replaced right rear impact sensor (part number varies by production date). Installed a heat insulation pad (included in OEM repair kit) between the new sensor and body mounting surface to keep sensor operating temperature below 85°C.
BYD DTC AI Analysis

Aftermarket sensor compatibility issue

✓
2020 Qin petrol variant. After an unauthorised repair shop replaced the right rear impact sensor, DTC B16F0 appeared. Multimeter testing revealed a fixed resistance of approximately 200 Ω between the signal output terminal and housing on the aftermarket sensor; a genuine sensor should read high impedance. The cause was an internal circuit design defect in the aftermarket part—the signal output stage lacked complete isolation. Solution: Replaced with a genuine BYD sensor (verify part number via VDS), cleared the fault code, and the fault disappeared. Impact sensors must be genuine OEM parts. Aftermarket units can cause false triggering or functional failure due to mismatched electrical parameters.
BYD DTC AI Analysis

Wiring harness sheath wear caused intermittent short circuit

✓
2019 Yuan, 55,000 km. Airbag warning light illuminated intermittently. DTC B16F0 status: History/Intermittent. Inspection found the right rear collision sensor harness chafing where it passes through the floor-to-C-pillar junction. Repeated trunk opening and closing flexed the harness repeatedly, wearing through the corrugated tubing and abrading the wire insulation. This caused intermittent contact with the body panel when the vehicle vibrated. Insulation resistance tested with a megohmmeter showed normal readings at rest, but resistance dropped to <100 Ω when bending the harness. Repair: Cut out the worn harness section (approx. 20 cm), re-routed the wiring, added securing clips to prevent body panel contact, and fitted braided sleeving for extra protection.
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.