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B16A3-00

DTC B16A3-00 indicates an internal self-check failure or core function fault within the airbag control unit (SRS ECU) — Atto 3

Safety System

DTC B16A3-00 indicates an internal self-check failure or core function fault within the airbag control unit (SRS ECU).

Specifically, this code indicates the ECU detects an internal processor fault, EEPROM memory error, abnormal internal power reference voltage, or SRS-CAN (Supplemental Restraint System CAN bus) communication interruption during the startup self-check or operation.

In BYD Qin series models, the SRS ECU integrates crash criteria algorithms, high-voltage interlock cut-off control logic, and multi-sensor data fusion functions.

This fault causes the airbag system to enter Fail-Safe mode, disabling the deployment of airbags, side curtain airbags, seat belt pretensioners, and the high-voltage system emergency cut-off function, while illuminating the instrument cluster SRS warning lamp.

If a collision occurs, the occupant protection system will fail and the high-voltage battery may not disconnect automatically, creating an extremely high safety risk.

5
Cases Logged
Real-World Cases
BYD DTC AI Analysis

2017 Qin EV300 SRS ECU internal memory fault

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At 82,000 km, the SRS lamp stayed on constantly. Retrieved active fault code B16A3-00; freeze frame data showed battery voltage at 11.8 V (low) when the fault occurred. Checked ECU power supply: normal. Attempted software upgrade, but the ECU did not respond. Disassembled the ECU and found cracked solder joints on the internal EEPROM chip (93C66), causing loss of configuration data. Replaced the SRS ECU assembly, performed online coding and sensor calibration. Fault resolved.
BYD DTC AI Analysis

2017 Qin 100: SRS system failure after water ingress

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Vehicle waded through approximately 30 cm of water. After repairs, the instrument cluster displayed an airbag fault. Retrieved DTC B16A3-00 and multiple collision sensor communication faults. Found water inside the SRS ECU connector at the centre of the floor pan; pins had oxidised, showing green corrosion. Cleaned the connector and dried the wiring harness. Measured the CAN bus and found a short to ground (0.2 V). Replaced the wiring harness connector and applied waterproofing. The DTC became intermittent and has not returned after clearing.
BYD DTC AI Analysis

2018 BYD Qin EV450: Aftermarket modifications causing CAN bus interference

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Owner installed a non-OEM dashcam and tapped power from the SRS fuse. The SRS warning lamp illuminated intermittently while driving. Diagnostics showed an intermittent B16A3-00 fault. Measurements found the aftermarket device generated pulse voltage spikes at startup, causing SRS-CAN signal interference. Restored the original vehicle circuit, rewired the dashcam to ACC power, and added a filter capacitor. The fault has not recurred.
BYD DTC AI Analysis

2017 BYD Qin 80: Cannot clear DTCs after collision repair

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After a front-end collision, the front bumper and left fender were replaced. After the repair, the SRS light stayed on with DTC B16A3-00. Inspection found the left front impact sensor incorrectly installed (poor grounding due to insufficient torque), and the SRS ECU had recorded a collision event (Crash Locked). Replaced the left front impact sensor and installed it to the specified torque (8.5 N·m). Used a diagnostic tool to perform 'Crash Data Reset' and 'ECU Unlock'. System returned to normal.
BYD DTC AI Analysis

2017 BYD Qin EV300: Aging auxiliary battery triggers false alarm

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Vehicle was hard to start after sitting parked for 3 days, and the SRS warning light came on. A battery capacity test showed only 32% remaining, with voltage dropping to 9.2V during cranking, triggering DTC B16A3-00. Replaced the AGM battery (60Ah) and checked the alternator charging current. The fault code cleared but returned intermittently. Eventually traced the cause to a drifted low-voltage protection threshold in the SRS ECU. Updating the ECU software to the latest version permanently fixed the fault.
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.