Airbag control unit with part number KD5H-57K30A

What does the airbag control unit KD5H-57K30A do?

The KD5H-57K30A is the central control unit of the restraint system (SRS) at Mazda. It evaluates the crash sensors, decides in an emergency which airbags and seatbelt pretensioners are triggered, and monitors the system permanently.

Faults are reported via the airbag warning light, and the related information is stored in the fault memory.

An accident results in crash data being stored, after which the unit locks itself.

Why does the control unit KD5H-57K30A fail?

On the KD5H-57K30A, the most common cause is crash data stored from an accident, which arises even where no airbag has deployed. Further causes relate to ageing, connections and the power supply.

Crash data cannot be erased with an ordinary diagnostic tool. Airbag24 removes it during the repair of the unit.

The further causes at a glance:

• ageing electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes, for example from a weak battery or jump starting

How can you tell that the KD5H-57K30A is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently when the KD5H-57K30A is defective. Fault messages, a diagnostic tool with no contact to the control unit, or a fault memory that cannot be cleared may also appear. In an emergency, airbags and seatbelt pretensioners may then not trigger.

The light shows the condition of the system directly, regardless of how the car behaves in everyday use.

Anyone who sees it lit should have the system checked promptly.

Which vehicles is the KD5H-57K30A fitted in?

The KD5H-57K30A is fitted in these vehicles: Mazda CX-5 KE (2011-2015) and KE Facelift (2015-2017). This information only states which vehicles this type of unit is assigned to, nothing more.

Here you will find the vehicles to compare with your own car.

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

Firstly, compare the part number on the label of the removed unit with this page; this only confirms that you have the right unit. Secondly, have the fault memory read out before removal, because only this 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 KD5H-57K30A work?

Before removal, read out the fault memory and attach the log; after disconnecting the battery, remove the control unit. Create the repair order online, then send in the well-packed unit. At Airbag24, processing usually takes 3–4 working days.

Airbag24 examines the unit on the test bench once it arrives, repairs defective components, erases crash data and carries out a functional test.

Your own unit is then 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 KD5H-57K30A get to Airbag24?

You send the KD5H-57K30A in by parcel or, as an alternative, book a UPS collection for an extra charge. Airbag24 returns the unit by UPS after the repair.

The printed repair order belongs in the parcel, and the unit must be packed shock-proof.