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 8

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 Atto 8 indicates the airbag control unit's internal configuration data does not match the vehicle's actual hardware or has become corrupted, forcing the SRS system into fail-safe mode and potentially disabling airbag deployment. This medium severity issue commonly occurs after an incomplete coding procedure following SRS unit replacement or severe battery discharge corrupting stored data. Visiting an authorised dealer is required. Typical repair cost data is available based on 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Failure to complete the online configuration/coding procedure after replacing the SRS control unit (ACU) causes the default configuration in the new module to mismatch the vehicle's actual hardware.
  • 2Severe vehicle battery discharge or prolonged power disconnection erases or corrupts configuration data stored in the ACU internal EEPROM.
  • 3Interruption during the SRS software upgrade or flashing process (such as power loss or communication failure) caused incomplete writing of configuration data.
  • 4Failure to synchronize ACU configuration parameters after replacing airbags/sensors following a severe collision causes a hardware and software configuration mismatch.
  • 5CAN bus communication fault (such as a loose connection or interference) prevents the ACU from reading required 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 data and history records. 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 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, re-perform anti-theft matching and write 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.). Ensure the Coding Code matches the vehicle certificate information.
  • 5
    After completing the configuration, perform the 'SRS self-check' or 'system initialization', clear the fault code, and perform an ignition cycle test (ON-OFF-ON) to verify 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 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.