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B16A2-00

B16A2-00 indicates an internal fault or performance degradation in the airbag control unit (SRS ECU) — Atto 3

Safety System

B16A2-00 indicates an internal fault or performance degradation in the airbag control unit (SRS ECU).

This is not an external sensor or actuator issue, but an abnormality in the microprocessor, memory chip, power management module, or internal acceleration sensor on the ECU main board.

This fault causes the airbag system to enter a degraded mode or fail completely.

Front airbags, side airbags, and pretensioner seatbelts may fail to deploy normally during a collision.

It may also trigger a high-voltage interlock cut-off, preventing the vehicle from powering up or causing a loss of high voltage while driving.

This DTC is a Hard Fault.

Simply disconnecting the power usually cannot clear it.

Perform an in-depth diagnosis of the hardware or software status.

5
Cases Logged
Real-World Cases
BYD DTC AI Analysis

BYD Qin EV300: Intermittent airbag warning light while driving, DTC B16A2-00.

✓
The airbag warning light came on intermittently during normal driving. Retrieved DTC B16A2-00 (current). Inspection found the vehicle had aftermarket audio installed; removing the centre console had caused pin 15 (power) of the SRS ECU connector (KJB01) to partially back out, causing intermittent power loss. Re-crimped the pin and applied conductive grease. Fault resolved. ECU not replaced — this was a false ECU fault caused by poor terminal contact.
BYD DTC AI Analysis

Qin 100 SRS ECU locked after accident repair

✓
The vehicle sustained a front-end collision. The airbags did not deploy, but the impact damaged the front impact sensor. After repairs, the airbag warning light remained on in the instrument cluster. Retrieved DTCs B16A2-00 and B1650-00 (Collision Record Latched). Inspection found that the SRS ECU had recorded the collision event, but the trigger voltage did not reach the deployment threshold, causing the ECU to enter Crash Mode. Attempted the Crash Data Clear procedure per the workshop manual, but it failed. Diagnosed physical damage to the ECU internal memory. Replaced the SRS ECU with a new unit (Part No. BYD-3636100-XS), performed online coding and system calibration. Fault resolved.
BYD DTC AI Analysis

Qin EV450 cannot enter Ready mode, with DTC B16A2-00 and high-voltage interlock fault.

✓
The vehicle failed to power up. The instrument cluster displayed 'Powertrain Fault' and the airbag warning light stayed on. DTC scanning found both B16A2-00 and P1A3400 (high-voltage interlock fault) at the same time. Found the SRS ECU housing earth wire was not tightened during the accident repair, causing the ECU's internal reference ground to drift. This both misreported an ECU fault and sent a collision signal to the BMS via the CAN bus, triggering the high-voltage shutdown. After tightening the earth wire and clearing the fault codes, the vehicle returned to normal operation. No ECU replacement necessary.
BYD DTC AI Analysis

Qin 80 software version defect caused B16A2-00 false positive

✓
In multiple complaint cases, the 2017 Qin 80 frequently logged DTC B16A2-00 during startup in low-temperature environments (below -10°C), with the fault clearing once the vehicle warmed up. BYD Technical Service Bulletin TSB-SRS-2018-03 confirmed early SRS software versions (below V1.02) had an overly sensitive internal accelerometer self-check at low temperatures. Solution: Upgraded the SRS ECU software to V1.05 to optimise the self-check thresholds. The fault has not reappeared since the upgrade, and no hardware replacement was necessary.
BYD DTC AI Analysis

Qin EV300 SRS ECU internal short circuit after wading through water.

✓
After the vehicle waded through water, multiple warning lights came on the instrument panel. Retrieved DTCs including B16A2-00, U0140 (lost communication with BCM), etc. Disassembly and inspection found water ingress at the SRS ECU mounting location (floor centre tunnel), with visible water stains and verdigris on the circuit board. Measured a short to ground in the ECU internal power supply module and determined water ingress had caused the internal voltage regulator chip to burn out. Replaced the SRS ECU, re-wrapped the wiring harness, and applied sealant for waterproofing. Fault resolved.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.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.
Data confidence: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.