AU
B16A0-00

DTC B16A0-00 indicates the airbag control unit (SRS ECU/ACM) detected a severe fault during its internal self-test — Atto 8

Safety System

DTC B16A0-00 indicates the airbag control unit (SRS ECU/ACM) detected a severe fault during its internal self-test.

This indicates a hardware-level anomaly in the ECU internal processor, memory, power regulation circuit, or safety monitoring circuit, rather than an external sensor or actuator fault.

The SRS ECU integrates crash discrimination algorithms, firing decision logic, and fault diagnostic functions.

This safety-critical fault means the ECU cannot guarantee reliable airbag and pretensioner deployment during a collision.

The root cause may be internal EEPROM data corruption, CPU calculation errors, abnormal internal voltage monitoring, or watchdog circuit triggering.

This fault typically requires ECU assembly replacement rather than repair.

The B16A0-00 fault code on the Atto 8 indicates a severe internal hardware fault in the airbag control unit (SRS ECU) detected during self-test, meaning the system cannot guarantee reliable airbag deployment in a crash. Severity is medium. Common causes include internal electronic component failure or power supply abnormalities. This typically requires ECU replacement by an authorised dealer. Typical repair cost data is available based on 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Internal ECU electronic component failure: Aged internal energy storage capacitor, damaged main control chip (MCU), or corrupted memory (EEPROM/Flash) data causing self-test failure.
  • 2Power supply system fault: Battery voltage too low (<9V) or too high (>16V), momentary voltage drop during ignition ON, or poor ground wire contact (oxidation at ground points G201/G301), causing abnormal operation of the ECU internal power management module.
  • 3Water ingress or corrosion: Vehicle wading, A/C condensate leakage, or improper engine bay cleaning causes corrosion and short circuits on the internal circuit board of the SRS ECU located in the centre tunnel (beneath the gear selector on Qin series).
  • 4Collision impact damage: Even if the airbags did not deploy, severe acceleration shock during an accident may crack solder joints on the ECU internal circuit board, damage the accelerometer, or deform the housing, causing internal short circuits.
  • 5Improper operation or power loss: Using non-genuine diagnostic equipment, disconnecting the battery for too long (>30 minutes), or improper jump-starting causes loss of internal ECU encrypted data or a VIN mismatch.
What To Do
  • 1
    Diagnostic confirmation: Use the BYD VDS2000/VDS6000 diagnostic tool to read fault codes. Confirm if only B16A0-00 is present or if accompanied by other communication faults (such as U0146). Record freeze frame data (vehicle speed, voltage, etc. at the time of the fault).
  • 2
    Basic circuit check: Measure the pins at SRS ECU connectors G09/G10 — constant power (B+) should be 12V ± 0.5V, IGN power should be 12V in the ON position, ground resistance <1Ω, CAN-H (2.6V) / CAN-L (2.4V) terminal resistance approximately 60Ω.
  • 3
    Power supply stability test: Use an oscilloscope to monitor supply voltage during startup and load changes. Check for voltage drops (<9V) or spikes (>16V). Focus inspection on fuse F4/9 (10A) and socket contact condition.
  • 4
    ECU physical inspection: Remove the centre armrest console and check the SRS ECU housing for deformation, cracks, water stains or signs of corrosion. Check the connector for oxidation, backed-out pins or signs of water ingress. If necessary, disassemble the ECU to inspect the circuit board.
  • 5
    Attempt software repair: Perform an 'ECU reset' or 'clear crash history' (if applicable). If the fault code is intermittent and not currently present, recalibrate the acceleration sensor. B16A0-00 typically indicates a hardware fault with a low software repair success rate.
  • 6
    Replace the SRS ECU: If the above checks show no abnormalities or reveal internal ECU damage, replace the airbag control unit assembly with a new unit. (Verify the part number for the vehicle model; e.g., Qin EV300 uses EQ-5820100.)
  • 7
    Online matching and programming: Use VDS to execute the 'Airbag ECU Replacement' procedure, perform online anti-theft matching (write the VIN, vehicle configuration code, and airbag configuration parameters), and perform acceleration sensor calibration (G-sensor Calibration).
  • 8
    System verification: Clear all fault codes and perform an ignition cycle test (OFF-ON-START). Confirm the SRS warning lamp turns off after the self-check (turns off after 6 seconds). Perform a simulated crash test (use the diagnostic tool to execute the 'Crash Output Test' to check circuit continuity without deploying the airbags). Finally, perform a road test for verification.
Real-World Cases
BYD DTC AI Analysis

BYD Qin Pro SRS warning light stays on (no collision history)

✓
Symptoms: After starting the vehicle, the airbag warning light stays on. VDS reads fault code B16A0-00. No other fault codes present. No accident history. Diagnosis: ECU supply voltage 12.4V (normal). Ground connection good. CAN communication normal. No visible damage to the ECU exterior. Power reset and software reset both ineffective. Resolution: Replaced the airbag control unit. Used VDS to perform online matching (wrote VIN and configuration data). After replacement, the warning light turned off and the system self-test passed.
BYD DTC AI Analysis

BYD Song MAX SRS system fault after accident repair

✓
Symptoms: After a minor front-end collision repair, the instrument cluster displayed “Please check SRS system”. VDS retrieved DTCs B16A0-00 (SRS ECU fault) and B1600-00 (driver airbag open circuit). Diagnostic process: Checked the driver airbag resistance (2.3Ω) and wiring harness connections; both normal. Removed and inspected the SRS ECU, finding the housing slightly deformed from accident impact and fine cracks on the internal circuit board. Resolution: Replaced the SRS ECU assembly, along with the deployed driver airbag and seatbelt pretensioners. Cleared the collision history and completed system matching using VDS.
Original source ↗
BYD DTC AI Analysis

Intermittent SRS warning light on BYD Tang DM

✓
Symptoms: SRS warning light intermittently illuminated while driving, occasionally extinguishing after an ignition cycle. Intermittent history fault code B16A0-00 stored. Diagnosis: ECU voltage monitoring found a momentary drop to 9V when switching the ignition. Inspection revealed poor contact at the F4/9 fuse holder in the engine bay fuse box, degraded internal energy storage capacitors (reduced capacity) inside the SRS ECU, and an owner-fitted dashcam wired directly to constant power, causing voltage fluctuations. Resolution: Repaired the poor contact at the F4/9 fuse holder. Rewired the dashcam to ACC power. Replaced the aged SRS ECU and performed programming.
BYD DTC AI Analysis

SRS ECU corrosion fault in water-damaged BYD e5

✓
Symptoms: After flood damage repair, vehicle would not enter READY mode. Instrument cluster displayed "Check SRS system" warning. Retrieved fault codes B16A0-00 and U0146 (loss of SRS communication). Diagnosis: Inspected SRS ECU mounting location under center console and found evidence of water ingress. Removed ECU; found severe internal circuit board corrosion and oxidized G09 connector pins. Power supply circuits measured normal, but ECU would not communicate. Resolution: Replaced SRS ECU. Cleaned oxidation from G09 connector using electronic cleaner and conductive grease. Inspected and replaced damaged floor harness. Performed online programming.
BYD DTC AI Analysis

BYD Yuan EV lost data after replacing the 12V battery.

✓
Symptoms: After a non-AGM standard battery was installed at an independent workshop, the SRS warning light stayed on. Retrieved DTCs B16A0-00 and B1691-00 (factory encryption error). Diagnosis: The battery had been disconnected for over an hour. Checking the ECU data found a VIN mismatch and internal encryption verification failure. The vehicle had no collision history, and the ECU showed no physical damage. Resolution: Used BYD VDS to perform the ‘Airbag ECU Replacement’ procedure — rewrote the VIN and configuration parameters, ran online encryption verification, and cleared the codes. The system returned to normal. Recommendation: Keep the power uninterrupted when replacing the battery.
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.