AU
B16AD-00

DTC B16AD-00 indicates an internal fault or communication error in the Supplemental Restraint System Electronic Control Unit (SRS ECU) — Atto 8

Safety System

DTC B16AD-00 indicates an internal fault or communication error in the Supplemental Restraint System Electronic Control Unit (SRS ECU).

As the core module of the airbag system, this control unit monitors vehicle collision acceleration in real time, processes crash sensor signals, determines airbag deployment timing, and drives the ignition circuits.

This fault may force the airbag system into Fail-Safe Mode, preventing the front dual airbags, side airbags, and curtain airbags from deploying during a collision.

The condition may also cause seat belt pretensioner failure and disrupt the crash fuel cut-off function.

The root cause typically involves an ECU internal microprocessor or memory failure, an abnormal 12V power supply (overvoltage/undervoltage), or an ECU malfunction resulting from a CAN network communication disruption, rather than a single sensor fault.

The B16AD-00 fault code on the Atto 8 indicates an internal fault or communication error in the Supplemental Restraint System (SRS) control unit that manages airbag deployment. Severity is medium. Common causes include internal circuit board faults or abnormal power supply. An authorised dealer must diagnose and repair the issue. Typical repair cost data is available from 4 recorded cases.
4
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1SRS ECU internal circuit board fault (e.g., filter capacitor aging, main control chip dry solder joints, or damage)
  • 2Abnormal power supply (unstable battery voltage, blown dedicated SRS fuse, poor or corroded ECU ground)
  • 3CAN bus communication fault (short circuit, open circuit, abnormal terminating resistor, or signal interference on the powertrain CAN or dedicated airbag CAN)
  • 4Vehicle wading or high-humidity environments cause internal ECU short circuits or PCB corrosion (the Qin series ECU mounts low and is prone to water ingress).
  • 5Incorrect vehicle repair after an accident (corrupted ECU data, uncleared crash record, or impact damage to hardware)
What To Do
  • 1
    Use the BYD dedicated diagnostic tool (VDS 2000 or VDS 2100) to read all fault codes. Verify B16AD-00 is a Current DTC, not a history DTC, and check for accompanying communication fault codes (codes starting with U).
  • 2
    Check the SRS ECU power supply circuit: Measure the voltage at the ECU connector B+ terminal (constant power) and IGN terminal (ignition switch power). The standard value is 11-14 V. If the voltage is below 10 V or above 16 V, repair the power supply system.
  • 3
    Check the ground circuit: Measure the resistance between the ECU ground pin and body ground. The resistance must be less than 1 Ω. If the resistance is too high, clean the ground point and tighten the bolt.
  • 4
    Check CAN communication: Measure resistance between diagnostic connector pin 6 (CAN-H) and pin 14 (CAN-L) (60Ω±5Ω) and voltage to ground (CAN-H: 2.5-3.5V, CAN-L: 1.5-2.5V). If abnormal, check the wiring harness for short or open circuits.
  • 5
    Check the ECU connector (usually located under the centre console or in front of the gear selector) for oxidation, looseness, or signs of water ingress. If necessary, clean with electrical contact cleaner and apply conductive grease.
  • 6
    If all circuit measurements are normal, perform the SRS ECU replacement procedure: disconnect the negative battery terminal and wait 3 minutes → remove the old ECU → install the new ECU → reconnect the power supply → use the diagnostic tool to perform ECU online programming (Coding) and write the crash threshold.
  • 7
    Clear the fault code and perform a system self-check. Confirm the airbag warning lamp completes its self-check and turns off within 6 seconds of turning the ignition switch ON.
  • 8
    Use an airbag simulator to perform a static deployment test (not an actual vehicle collision) to verify the ignition circuit resistance (2.0-3.0Ω) and system functional integrity.
Real-World Cases
BYD DTC AI Analysis

Water damaged the SRS ECU after the Qin EV300 drove through water.

✓
A 2017 Qin EV300 had the airbag warning light on the dash stay on after driving through flood water in heavy rain. VDS scan retrieved B16AD-00 (current fault) and B1600-00 (ECU power supply abnormal). Inspection found the SRS ECU mounted on the floor beneath the centre console had visible water staining and PCB corrosion inside from the water ingress. Measured ECU power supply pin voltage at 12.4V, which was normal, but CAN communication voltage was abnormal. Replaced the SRS ECU with a new unit, then dried, cleaned, and waterproofed the wiring harness connectors. Cleared the fault codes, and the system self-test passed.
BYD DTC AI Analysis

Qin 100 aftermarket audio installation caused voltage instability, triggering a fault.

✓
Owner reported that after fitting a high-power audio system to their 2017 Qin 100, the SRS warning light would occasionally illuminate while driving, then clear after turning the vehicle off and restarting. Historical DTCs showed B16AD-00. Inspection found the modification shop had taken power directly from the battery without installing a voltage stabiliser. When the high-power audio system operated, battery voltage instantly dropped below 9V, triggering SRS ECU undervoltage protection. Technicians rewired the system, installed a dedicated voltage stabiliser, and replaced the SRS ECU that had recorded voltage abnormality events (the ECU had internally flagged the fault).
BYD DTC AI Analysis

Qin EV450 ECU internal accelerometer fault after accident repair

✓
Following front-end collision repairs on a 2018 Qin EV450, the airbag warning light remained illuminated and the seatbelt pretensioners would not reset. The scan revealed DTC B16AD-00 and multiple impact sensor communication faults. Further inspection showed that although the collision force hadn't reached the airbag deployment threshold, the impact had physically damaged the MEMS accelerometer inside the ECU. Replaced the ECU, completed online programming (writing the vehicle VIN and crash parameters), then used the diagnostic tool to run 'Collision Output Clear' and 'Configuration Reset'. The system returned to normal.
BYD DTC AI Analysis

Qin 80 ECU connector oxidised after long-term parking

✓
A 2017 Qin 80 displayed an SRS fault on startup after sitting for three months. Diagnostics revealed DTC B16AD-00 accompanied by U0155 (lost communication with the instrument cluster). Inspection showed the floor-mounted ECU connector had oxidised copper pins due to damp conditions; contact resistance had increased to 5Ω (normal <0.5Ω). Cleaning the connector pins and applying electronic protectant restored communication, but the ECU still logged an internal fault and required replacement. Long-term oxidation caused an unstable power supply, which damaged the ECU's internal circuitry.
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.