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 — Seal 6 EV

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.

The B16AC00 fault code on the Seal 6 EV indicates a configuration error in the airbag control unit (SRS ECU), where stored data doesn't match the vehicle's actual hardware setup or the data is corrupted. This medium-severity fault forces the airbag system into fail-safe mode, potentially disabling deployment. Common causes include incomplete coding after ACU replacement or data corruption from battery discharge. Visit an authorised dealer for repair. Typical repair cost data is available based on 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Incomplete online configuration/coding procedure after replacing the SRS control unit (ACU), causing the default configuration in the new module to mismatch the vehicle's actual hardware.
  • 2Severe vehicle battery discharge or prolonged disconnection caused the 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 an incomplete configuration data write.
  • 4Replacing some airbags/sensors after a severe collision without updating the ACU configuration parameters accordingly causes a hardware and software configuration mismatch.
  • 5CAN bus communication fault (such as loose connections or interference) prevents the ACU from reading necessary vehicle configuration information from the BCM or other modules (such as 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 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 normal values (approximately 60Ω 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) and 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 the 'SRS self-check' or 'system initialization', clear the fault code, and perform an ignition cycle test (ON-OFF-ON). 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 Seal 6 EV Fault Codes
B1108For 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.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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Seal 6 EV →Seal 6 EV 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.