AU
B16C0-00

DTC B16C0-00 indicates the Airbag Electronic Control Unit (SRS ECU) detected an abnormality during its internal self-check — Atto 8

Safety System

DTC B16C0-00 indicates the Airbag Electronic Control Unit (SRS ECU) detected an abnormality during its internal self-check.

This typically indicates a hardware fault in the ECU internal processor, memory, or power management module, or a communication failure between the ECU and the vehicle CAN network.

This fault forces the airbag system into fail-safe mode.

In a collision, the system may fail to deploy the airbags and seat belt pretensioners, or activate the high-voltage interlock cut-off function, posing a severe safety risk.

This DTC is a hard fault and generally will not clear automatically.

Perform a hardware-level repair or replace the ECU.

The B16C0-00 fault code on the Atto 8 indicates the airbag control unit has found an internal fault during its self-check. Severity is medium, but it can affect airbag, seat belt pretensioner, and high-voltage cut-off operation. Common causes include ECU circuit board damage or an unstable power or ground supply. Visit an authorised dealer for diagnosis, hardware repair, or ECU replacement. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Damaged components on the SRS ECU internal circuit board (e.g., bulging electrolytic capacitor, cold solder joint on the main control chip, or chip breakdown)
  • 2ECU power supply circuit fault (unstable voltage at constant power B+ or ignition power IG1, poor fuse contact, or oxidized ground point)
  • 3Vehicle CAN network communication fault (short circuit between CAN-H and CAN-L, short to ground, or wiring open circuit prevents the ECU from communicating with the vehicle)
  • 4ECU internal memory data corruption or software version defect (interrupted flashing process or electromagnetic interference causing program loss)
  • 5Vehicle wading or high humidity causes ECU seal failure, resulting in internal PCB corrosion or pin oxidation.
What To Do
  • 1
    Use the VDS diagnostic tool to read the complete DTCs and freeze frame data. Confirm the vehicle speed, power supply voltage, temperature, and other environmental parameters at the time of the fault. Attempt to clear the fault code to verify if the fault is intermittent.
  • 2
    Disconnect the battery negative terminal, wait 3 minutes, then remove and inspect the SRS ECU (usually located under the center console or at the bottom of the center armrest box). Check the housing seal and inspect the interior for water stains, burn marks, or physical damage.
  • 3
    Keep the ECU wiring harness connector connected. Measure the voltage between the power supply terminals (B+, IG1) and ground (12V ± 0.5V). Measure the ground terminal resistance (< 1 Ω). Check the CAN-H (2.5–3.5V) and CAN-L (1.5–2.5V) voltages, and the terminating resistance (approx. 60 Ω).
  • 4
    If the wiring is normal, update the ECU software (using the latest VDS version and official firmware). After updating, perform coding and execute an airbag system function test.
  • 5
    If the software update fails, replace the SRS ECU with the same model (the part number must match exactly). Perform online configuration, write the VIN, and calibrate the crash sensor zero point on the new ECU.
  • 6
    After reassembly, connect the diagnostic tool to clear the fault code. Perform static and dynamic road tests to verify B16C0-00 does not return and the airbag warning lamp turns off normally.
Real-World Cases
BYD DTC AI Analysis

Qin EV300 SRS ECU supply voltage instability causing intermittent fault

✓
A 2017 Qin EV300 had an intermittent airbag warning light while driving. The scanner retrieved DTC B16C0-00. Inspection found a loose connection at the ECU power fuse FB11 (15A) socket, causing the ignition switch IG1 supply voltage to fluctuate severely between 11.2–13.8V. The technician sanded the fuse socket contacts; voltage stabilized at 12.4V, and the fault code did not return.
Original source ↗
BYD DTC AI Analysis

Song DM SRS ECU internal corrosion after water wading

✓
After driving through flood water, the airbag warning light stayed on with DTC B16C0-00 logged. Upon disassembly, found the ECU mounted beneath the floor. The seal had perished, allowing water ingress and causing green copper corrosion on the internal PCB. Cleaned and dried the module but the fault remained. The internal voltage regulator circuit output measured out of spec. Replaced the SRS ECU, performed crash sensor calibration, and cleared the fault.
BYD DTC AI Analysis

Tang EV: CAN Network Short Circuit Triggers SRS ECU Communication Fault

✓
After the collision repair, the dashboard displayed an airbag warning. Diagnosis found DTC B16C0-00 accompanied by multiple U-code communication faults. Measuring pins 6 (CAN-H) and 14 (CAN-L) at the diagnostic port showed resistance of only 12Ω (normal 60Ω). Step-by-step tracing identified damaged CAN wire insulation on the right A-pillar wiring harness from the previous repair, causing abnormal parallel resistance. The fault cleared after repairing the harness.
BYD DTC AI Analysis

Qin Pro EV SRS ECU software version defect

✓
Detected DTC B16C0-00 during pre-delivery inspection (PDI). Checked power supply and earth connections – both normal. ECU showed no external damage. Cleared the fault code and switched the vehicle off and on – fault immediately returned. Performed online ECU software update using VDS (upgrade from V2.1.3 to V2.2.0). After the update, completed system configuration and function testing. Fault completely resolved.
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.