AU
B16AC00

B16AC00 (Config_Error) indicates the internally stored configuration data in the airbag control unit (SRS ECU/ACU) does not match the actual vehicle hardware configuration, or the configuration data checksum failed — Atto 3

Safety System

B16AC00 (Config_Error) indicates the internally stored configuration data in the airbag control unit (SRS ECU/ACU) does not match the actual vehicle hardware configuration, or the configuration data checksum failed.

In BYD E2, E3, Qin EV, and similar models, this fault typically means the ACU coding data and vehicle configuration parameters (such as airbag quantity, seat belt pretensioner configuration, crash sensor type, and child seat recognition configuration) do not match the actual installed equipment, or data corruption occurred during writing or storage.

This fault forces the SRS system into fail-safe mode, potentially disabling airbag deployment or causing complete system failure.

This is a critical fault affecting passive safety.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Incomplete online configuration/coding procedure after replacing the SRS control unit (ACU), resulting in a mismatch between the default configuration in the new module and the actual vehicle hardware.
  • 2Severe vehicle battery discharge or prolonged power disconnection causes loss or corruption of configuration data stored in the ACU internal EEPROM.
  • 3Interruption during the SRS software upgrade or flashing process (such as power loss or communication failure), causing incomplete configuration data writes.
  • 4Some airbags/sensors were replaced after a severe collision, but the ACU configuration parameters were not updated, causing a hardware and software configuration mismatch.
  • 5CAN bus communication fault (e.g., loose wiring connections or interference) prevents the ACU from reading necessary vehicle configuration information from the BCM or other modules (e.g., VIN verification failure).
What To Do
  • 1
    Use the official BYD diagnostic tool (BYD-EDS or VDS) to read complete fault code information, including Freeze Frame data and history records, and check for other accompanying communication or hardware fault codes.
  • 2
    Check the power supply, ground, and CAN line connections of the SRS control unit (usually located under the center console or gear selector). Measure the voltage and terminal resistance to verify they are normal (approximately 60 Ω between CAN-H and CAN-L).
  • 3
    Check if the vehicle VIN matches the VIN stored in the ACU. If they do not match, perform anti-theft matching and rewrite the configuration.
  • 4
    Perform the 'SRS System Configuration/Coding' function (online configuration) to rewrite the correct configuration data based on the actual vehicle hardware configuration (number of airbags, pretensioner configuration, etc.). Verify the Coding Code matches the vehicle certificate information.
  • 5
    After completing the configuration, run 'SRS self-check' or 'system initialization'. Clear the fault code, perform an ignition cycle test (ON-OFF-ON), and confirm B16AC00 does not return and the airbag warning light turns off normally.
Real-World Cases
BYD DTC AI Analysis

E2: Replaced airbag ECU without configuration, causing Config_Error

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Replaced the airbag control unit (ACU) on a 2019 BYD E2 due to water damage. After fitting the new unit, the airbag warning light stayed on constantly. Retrieved DTC B16AC00 Config_Error. Found the new ACU contained blank configuration (default coding) that did not match the E2 specification. Used the BYD VDS diagnostic tool to execute the 'Online Configuration' function and entered the correct coding for this model (00120001). After completing coding, cleared the fault code and the system returned to normal.
BYD DTC AI Analysis

Configuration data lost on Qin EV after prolonged battery discharge

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A 2019 Qin EV experienced a complete 12V battery discharge (voltage <5V) after the owner left it unused for an extended period. After charging the battery and starting the vehicle, the dashboard displayed an airbag fault. Diagnostics found DTC B16AC00 and multiple communication fault codes. Analysis determined that the severe battery discharge had corrupted the ACU internal memory data. The technician used a diagnostic tool to rewrite the vehicle configuration data and upgrade the ACU software to the latest version, which fixes the low-voltage data protection logic. The fault was resolved, and the owner was advised to avoid prolonged battery discharge.
BYD DTC AI Analysis

E3 software update interrupted causing configuration error

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While updating the SRS software on a 2020 E3 at the dealership, the diagnostic tool cable came loose and interrupted the update. After restarting, the airbag light came on with DTC B16AC00. The ACU was in a corrupted software state. The technician connected a backup power supply for stable voltage, re-entered 'SRS Programming' mode, ran 'Initialisation' to clear the error data, then fully flashed the latest software and reconfigured vehicle parameters. Problem solved.
BYD DTC AI Analysis

Mercedes-Benz B16AC00 Case Reference (SIM Card Configuration Fault)

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Note: Search results show B16AC00 in Mercedes-Benz models represents a communication module SIM card configuration fault. Although the DTC is identical, its meaning differs. For reference: A Mercedes-Benz vehicle displayed B16AC00, along with MB-App connection failure and no network service. Technicians diagnosed a SIM card configuration error in the RAMSES control unit and resolved it by performing 'Initial Start Up' to reconfigure the communication module. The lesson for BYD repairs: Config_Error faults typically need reconfiguration/initialisation to resolve.
Original source ↗
BYD DTC AI Analysis

Loose connection in SRS wiring harness caused configuration read failure

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A Qin EV's airbag warning light came on intermittently after driving on rough roads. The stored DTC was B16AC00 (intermittent). Inspection revealed the ACU CAN-L line connector pin had backed out, causing packet loss during high-speed communication and preventing the ACU from reading the configuration data correctly. Repaired the connector and applied conductive grease; the fault did not return. Distinguish this type of fault from pure software configuration errors, as poor hardware contact can also trigger Config_Error.
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: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.