What is a Mazda Axela BM airbag control unit?
A Mazda Axela BM airbag control unit is the central control unit of the Supplemental Restraint System (SRS), which manages all occupant safety in the event of an accident. It processes signals from impact sensors, deploys airbags and seatbelt pretensioners, stores important crash data, and enables diagnostics of the entire safety system.
The control unit continuously monitors all airbags, seat belt pretensioners, and other safety-relevant components in the vehicle. It is crucial for the passive safety of the Mazda 3 III (BM) from 2013 to 2018.
This module ensures that all systems react synchronously and correctly in an emergency. It is installed in both the hatchback and sedan versions of the Mazda Axela BM.
Why is the Mazda Axela BM airbag control unit defective?
The Mazda Axela BM airbag control unit often malfunctions because it stores crash data after an accident, preventing it from being reused without a reset, or due to internal hardware errors. Communication problems in the vehicle's CAN bus network can also cause the control unit to malfunction or exhibit failures.
Internal memory problems or module errors are common causes signaled by error codes B0010 or B0070. These directly indicate a malfunction in the control unit itself.
A broken CAN bus connection can also cause a failure, resulting in error codes such as U0151 or C2011. An unstable battery voltage (U3003) can also lead to malfunctions.
Repairing the airbag control unit is often necessary to restore full functionality to the safety system and clear the airbag warning light.
Common error codes for Mazda Axela BM airbag control unit repair
When diagnosing a faulty Mazda Axela BM airbag control unit, specific error codes will appear that indicate internal problems or communication disruptions within the vehicle's network. These codes are crucial for identifying the exact cause of a failure and initiating the necessary repair or replacement to ensure safety.
- B0010 → Internal control unit error → Memory problem or incorrect data in the airbag ECU.
- B0070 → Control unit error → Airbag ECU communication or internal module problem.
- C2011 - C2014 → Communication error diagnostic device ↔ airbag control unit → Malfunction of the CAN bus connection to the airbag ECU.
- U0151 → CAN bus connection to the airbag control unit faulty → interruption of the data line to the airbag ECU.
- U0001 → Communication error in the control unit network → General malfunction of the network connection to the airbag ECU.
- U0073 → Control unit communication fault → Faulty communication with the airbag ECU in the vehicle network.
- U3000 → Control unit function faulty → Internal functional error of the airbag ECU.
- U3003 → Battery voltage out of range → Voltage problem affecting the airbag ECU.
For a precise diagnosis and clearing of these error codes, a manufacturer-specific diagnostic tool is required at the workshop. Simple OBD2 scanners often cannot read all relevant SRS codes.
Which part numbers are relevant for the Mazda Axela BM airbag control unit repair?
For the successful repair or replacement of a Mazda Axela BM airbag control unit, specific OEM part numbers are essential to ensure 100% compatibility. Only exact matching numbers guarantee the correct function of the safety system and avoid compatibility issues after installation and coding.
The OEM part numbers listed below are verified and suitable for the Mazda Axela BM (Mazda 3 III, built 2013-2018) airbag control unit.
It is important to use only these numbers, as older models or other parts are incompatible and may compromise safety.
- BHS2-57-K30A (Mazda Original)
- B45A-57-K30A (Mazda Original)
- BHAA57K30A (Mazda original, tested replacement module)
After replacing the airbag control unit, programming to the vehicle identification number (VIN) by a specialist workshop is usually required. This ensures complete integration and functionality in the vehicle.