Airbag control unit with part number BFF4-57K30

What does the airbag control unit BFF4-57K30 do?

The airbag control unit BFF4-57K30 coordinates the restraint system (SRS) of Mazda. It processes the signals from the crash sensors and decides in a collision which airbags and seatbelt pretensioners are triggered.

It also monitors the system continuously. Detected faults are shown via the airbag warning light, so the driver can see them.

In the event of a registered accident it creates crash data and then remains locked.

Why does the control unit BFF4-57K30 fail?

Stored crash data after an accident are the most common cause, even if no airbag was triggered; a standard diagnostic tool cannot remove them. In addition, aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes such as those from a weak battery or jump-starting come into consideration.

An airbag that did not deploy does not mean that nothing was stored. The data remain in the unit until the repair removes them.

The other causes concern ageing and external influences on the electronics and connectors. Whether one of them applies is shown by the examination.

How can you tell that the BFF4-57K30 is defective?

A permanently or intermittently lit airbag warning light in the instrument cluster is the typical sign. An error message in the instrument cluster, no connection to the diagnostic tool, or a fault memory that cannot be cleared also point to a problem. In an emergency, airbags and seatbelt pretensioners may then not be able to trigger.

The light shows the fault.

Even a fault that appears only intermittently justifies reading out the fault memory.

Which vehicles is the BFF4-57K30 fitted in?

Check by the part number whether your vehicle is affected. The control unit BFF4-57K30 is fitted in these vehicles: Mazda Mazda3 BL (2009-2011) and BL Facelift (2011-2013).

The affected vehicles at a glance:

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

Comparing the part number on the label of the removed unit with this page only confirms that it is the right unit. Whether the control unit is defective or a connector or cable is the cause only becomes clear after the fault memory has been read out. Have it read out beforehand.

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 BFF4-57K30 work?

Have the fault memory read out first and add the log. Only after disconnecting the battery do you remove the control unit. Then create a repair order online. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the unit on the test bench, replaces defective components and erases stored crash data. A function test follows, and then the unit is sent back to you.

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 BFF4-57K30 get to Airbag24?

Either you post the unit as a parcel or you book a UPS collection for an extra charge. The return after the repair is by UPS.

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