Airbag control unit with part number BCP8-57K30

What does the airbag control unit BCP8-57K30 do?

The airbag control unit BCP8-57K30 is the central control unit of the restraint system (SRS) for Mazda. It evaluates the signals from the crash sensors, decides within milliseconds whether to trigger the airbags and seatbelt pretensioners, and monitors the system.

If the unit detects a fault, it reports it via the airbag warning light in the instrument cluster and stores it in the fault memory.

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

Why does the control unit BCP8-57K30 fail?

Stored crash data is the most common cause, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The crash data remains in the unit until Airbag24 erases it during the repair. The other causes concern the electronics themselves and their connections.

Aged components lose performance over time, and cold solder joints on the circuit board can interrupt contacts. Voltage spikes, for example from a weak battery or a jump start, put additional strain on the electronics.

How can you tell that the BCP8-57K30 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and an error message appears in the instrument cluster. The diagnostic tool finds no connection to the control unit, and the fault memory cannot be cleared. In an emergency, the airbags and seatbelt pretensioners may then fail to deploy.

If the airbag warning light is on, the system is indicating a fault it has detected. Therefore, have the fault memory read out promptly.

A missing connection to the diagnostic tool is also a sign that needs to be investigated.

Which vehicles is the BCP8-57K30 fitted in?

The control unit BCP8-57K30 is fitted in these vehicles: Mazda Mazda3 BL (2009-2011) and BL Facelift (2011-2013).

The following vehicles belong to this part number:

• 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. This ensures that you have the right unit in front of you, but says nothing about its condition. Have the fault memory read out beforehand. Only this log shows whether the control unit is defective or whether a plug or a cable 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 BCP8-57K30 work?

First, have the fault memory read out and enclose the log. Then disconnect the battery and remove the control unit. Next, create a repair order online and send in the unit, well packed.

Airbag24 checks the control unit on the test bench, carries out repairs where components are defective, erases stored crash data and performs a function test. Only then is your own unit returned to you. Processing usually takes 3–4 working days.

The order of these steps is a safety measure, because the control unit is only removed after the battery has been disconnected. 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 BCP8-57K30 get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Enclose the printed repair order and pack the unit shockproof.