Airbag control unit with part number BFD2-57K30

What does the airbag control unit BFD2-57K30 do?

The airbag control unit BFD2-57K30 controls the restraint system (SRS) for Mazda. It evaluates the signals from the crash sensors, decides in a crash within milliseconds which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

It reports faults via the airbag warning light, which is visible in the instrument cluster. This keeps the state of the system traceable even without a workshop visit.

After an accident the control unit stores crash data and locks itself.

Why does the control unit BFD2-57K30 fail?

On the BFD2-57K30, the most common cause after an accident is stored crash data, even if no airbag has triggered; a normal diagnostic tool cannot erase them. Other causes are aged electronic components, cold solder joints, moisture and corrosion at connectors, and voltage spikes.

Crash data is a record, not a defect in the electronics. The fact that it stays in the unit does explain, however, why reading it out alone does not fix the fault.

The remaining causes concern the electronics themselves. Components age, solder joints can go cold, and moisture or corrosion at connectors disturb the signals. Voltage spikes arise, for example, with a weak battery or through jump-starting.

How can you tell that the BFD2-57K30 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently. In addition there is a fault message in the instrument cluster, no connection from the diagnostic tool to the control unit, or a fault memory that cannot be cleared.

A defect on the BFD2-57K30 can be recognised from these signs, and the warning light makes it visible as soon as the system detects it.

In an emergency, airbags and seatbelt pretensioners may then possibly not trigger. Therefore have the fault checked promptly.

Which vehicles is the BFD2-57K30 fitted in?

The control unit BFD2-57K30 is fitted in these vehicles: Mazda Mazda3 BL (2009-2011) and BL Facelift (2011-2013). The list shows the vehicles known to us for this number.

The vehicles are shown in detail in the following overview.

• Mazda Mazda3 BL (2009-2011)
• Mazda Mazda3 BL Facelift (2011-2013)

Compare the part number on the label of the removed unit with this page so that you can be sure you have the right unit. Also have the fault memory read out beforehand, because only this record shows whether the control unit is defective or a connector is the cause.

For the same vehicles, we also repair control units with the part numbers 0 285 001 960, B39G-57K30, BCF1-57K30, BFB6-57-K30, BFD1-57K30.

How does the repair of the BFD2-57K30 work?

First read out the fault memory and attach the log. Then disconnect the battery and only then remove the control unit BFD2-57K30. Then create a repair order online and send the unit in well packed.

At Airbag24 the team checks the unit on the test bench, repairs defective components and erases stored crash data. A function test follows, and your own unit then goes back to you.

Processing at Airbag24 usually takes 3–4 working days. These days cover only checking, repairing and testing at our end. Our repairs come with 2 years' statutory liability for defects. The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.

How does the control unit BFD2-57K30 get to Airbag24?

The unit goes to Airbag24 as a parcel, or you arrange a UPS collection for an extra charge. After the repair Airbag24 returns the control unit BFD2-57K30 by UPS.

Put the printed repair order in the parcel and pack the unit shock-proof.