Airbag control unit with part number BELG-57K30

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

The airbag control unit BELG-57K30 controls the restraint system (SRS) of Mazda. It evaluates the crash sensors, determines in an accident which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

The unit works in the background and detects faults itself. The message goes to the airbag warning light in the instrument cluster, and the entry remains in the fault memory until it is cleared or dealt with.

After an accident the control unit stores crash data and locks itself. The following sections show what follows from this.

Why does the control unit BELG-57K30 fail?

Most often the cause is crash data stored after an accident, even if no airbag was triggered. A normal diagnostic tool cannot erase this data.

A fault also occurs without an accident. The other causes are:

• aged components in the electronics
• cold solder joints that lose contact
• moisture and corrosion at plug connections
• voltage spikes, for example from a weak battery or jump starting

One of these causes can act for a long time before it shows.

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

The airbag warning light in the instrument cluster stays on permanently or lights up intermittently, an error message appears, or the diagnostic tool does not find the control unit. If the fault memory cannot be cleared, the suspicion is justified.

The airbag warning light is the first thing to be noticed. If it burns continuously or flickers intermittently, the system is faulty and this should be checked.

As long as the system does not work without faults, airbags and seatbelt pretensioners may fail to deploy in an emergency. Therefore do not wait until the fault disappears on its own, because you cannot rely on that.

Which vehicles is the BELG-57K30 fitted in?

The control unit BELG-57K30 is fitted in these vehicles: Mazda CX-5 KE (2011-2015) and KE Facelift (2015-2017).

The list contains the vehicles for which this part number is known.

• Mazda CX-5 KE (2011-2015)
• Mazda CX-5 KE Facelift (2015-2017)

Before removing the control unit, have the fault memory read out. Then you know whether the unit is defective or only a plug or cable. Then compare the part number on the label of the removed unit with the information given here.

For the same vehicles, we also repair control units with the part numbers KA1C-57-K30A, KA1C-57K30, KD45-57K30B, KEAD 57K30 C, KR2757K30A.

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

First read out the fault memory and attach the log; then disconnect the battery and remove the control unit. Afterwards create the repair order online and pack the unit well.

Pack the unit well before sending it in. Make sure the repair order is completely filled in, so that processing can begin without queries.

Airbag24 checks the unit on the test bench, replaces defective components, deletes the crash data and carries out a function test. Processing usually takes 3–4 working days, after which your own unit goes 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 BELG-57K30 get to Airbag24?

You send the control unit BELG-57K30 as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 sends it back to you by UPS.

Put the printed repair order into the parcel and pack the control unit shockproof.