Airbag control unit with part number KB7W-57K30

What does the airbag control unit KB7W-57K30 do?

The airbag control unit KB7W-57K30 controls the restraint system (SRS) for Mazda. It processes the signals from the crash sensors and determines in an accident within milliseconds which airbags and seatbelt pretensioners are triggered. It shows faults in the system via the airbag warning light.

The unit monitors the system continuously while the vehicle is in operation. This includes the wiring, the sensors and the firing circuits.

After an accident, the control unit stores crash data and locks itself. Only the repair lifts this lock.

Why does the control unit KB7W-57K30 fail?

Stored crash data after an accident is the most common cause with the KB7W-57K30, even if no airbag was triggered. Other causes are aged electronics, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data cannot be erased with a normal diagnostic tool, which makes troubleshooting without a repair difficult. Airbag24 removes the data during the repair.

The other causes concern the electronics themselves. Components can age, solder joints can go cold, and moisture attacks plug connections. A weak battery or a jump start can cause voltage spikes that affect the unit.

How can you tell that the KB7W-57K30 is defective?

A defect on the KB7W-57K30 shows up as the airbag warning light in the instrument cluster, which lights up permanently or intermittently. Accompanying this are a fault message in the instrument cluster and a diagnostic tool that cannot connect to the control unit.

If the fault memory also cannot be cleared, that is a further sign. If the control unit is defective, the airbags and seatbelt pretensioners may fail to trigger in an emergency. So take the warning light seriously.

Which vehicles is the KB7W-57K30 fitted in?

The KB7W-57K30 is fitted in these vehicles: Mazda CX-5 KE (2011-2015) and KE Facelift (2015-2017).

The following overview shows the vehicles in which this control unit is installed.

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

Compare the number on the label of the removed unit with KB7W-57K30 on this page. This way you make sure it is the right unit. Have the fault memory read out beforehand, because only the log shows whether the control unit is defective or whether a plug or cable is the cause.

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 KB7W-57K30 work?

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

Airbag24 examines the unit on the test bench, repairs defective components, erases stored crash data and carries out a function test. Processing usually takes 3–4 working days. Afterwards, the unit is returned 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 KB7W-57K30 get to Airbag24?

You send in the control unit KB7W-57K30 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

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