Airbag control unit with part number KR27-57K30

What does the airbag control unit KR27-57K30 do?

In the Mazda, the airbag control unit KR27-57K30 coordinates the restraint system (SRS). It evaluates the crash sensors, decides in an accident within milliseconds whether to trigger the airbags and seatbelt pretensioners, and monitors the system continuously. It indicates faults via the airbag warning light.

After an accident, the unit stores crash data and locks itself. This property belongs to the protective function of the electronics and is built into the control unit itself.

The sensors deliver their readings continuously to the control unit. Only the evaluation there determines whether an airbag triggers.

Why does the control unit KR27-57K30 fail?

Stored crash data is the most common cause on the KR27-57K30, even when no airbag has deployed. It cannot be erased with a normal diagnostic tool. Further causes at a glance:

• aged electronic components
• cold solder joints
• moisture and corrosion at plug connectors
• voltage spikes, for example from a weak battery or a jump start

If no airbag has deployed, that does not mean nothing has been stored. Whether crash data is present is shown only by reading out the unit.

Airbag24 erases the crash data during the repair.

How can you tell that the KR27-57K30 is defective?

On the KR27-57K30, a defect first shows up through the airbag warning light in the instrument cluster, which lights up permanently or intermittently. Further indications are error messages, a diagnostic tool that cannot establish a connection, and a fault memory that cannot be cleared.

• Airbag warning light lights up permanently or intermittently
• Error message in the instrument cluster
• Diagnostic tool receives no connection to the control unit
• Fault memory cannot be cleared

In an emergency, the airbags and seatbelt pretensioners may possibly fail to trigger. Please have such a finding checked promptly.

Which vehicles is the KR27-57K30 fitted in?

The control unit KR27-57K30 is fitted in these vehicles: Mazda CX-5 KE (2011-2015) and KE Facelift (2015-2017).

Below you will find the list of vehicles that Airbag24 holds for this unit.

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

Compare the part number on the label of the removed unit with this page. This only ensures that it is the correct unit. Have the fault memory read out beforehand; only the result 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 KR27-57K30 work?

At Airbag24, checking, repairing and function testing the KR27-57K30 usually takes 3–4 working days. Beforehand, have the fault memory read out, disconnect the battery and only then remove the control unit.

Then create a repair order online and send the unit in well packed. Airbag24 checks it on the test bench, replaces defective components, erases stored crash data and carries out a function test. Then your own 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 KR27-57K30 get to Airbag24?

You send the KR27-57K30 as a parcel or have it collected by UPS for an extra charge. After the repair, Airbag24 returns the unit by UPS.

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