Airbag control unit with part number TK52-57K30

What does the airbag control unit TK52-57K30 do?

The airbag control unit TK52-57K30 is the central SRS control unit for Mazda. It processes the signals from the crash sensors, decides on triggering the airbags and seatbelt pretensioners within milliseconds in an impact, and monitors the system continuously. After an accident, it stores crash data and locks itself.

The unit stores detected faults in memory and indicates them via the airbag warning light.

Because the unit has to decide quickly in an emergency, flawless function is important.

Why does the control unit TK52-57K30 fail?

Stored crash data are among the causes that occur most often: they remain in the unit after an accident, even if no airbag has deployed. A normal diagnostic tool cannot clear them. Other causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

With crash data the situation is clear: the unit has recorded the event. Airbag24 removes this entry during the repair.

The other causes arise over time or through external influences. Electronic components change their properties, solder joints can go cold, and moisture acts on the plugs. Voltage spikes arise, for example, from a weak battery or when a jump-start cable is connected.

How can you tell that the TK52-57K30 is defective?

On the TK52-57K30, a defect shows itself through the airbag warning light in the instrument cluster, which lights up permanently or intermittently, and through an error message in the instrument cluster. The diagnostic tool does not reach the control unit, and the fault memory cannot be cleared.

The signs are:

• airbag warning light, permanently or intermittently
• error message in the instrument cluster
• no contact with the diagnostic tool
• fault memory cannot be cleared

Do not treat this as a minor matter: in an emergency, airbags and seatbelt pretensioners may possibly fail to deploy.

Which vehicles is the TK52-57K30 fitted in?

The TK52-57K30 is fitted in these vehicles: Mazda CX-9 TC (2016-2020) and TC Facelift (2020-2023).

The list shows the vehicles assigned to the unit.

• Mazda CX-9 TC (2016-2020)
• Mazda CX-9 TC Facelift (2020-2023)

First compare the part number on the label of the removed unit with this page, so that you can be sure it is the correct unit. Then have the fault memory read out. Only this 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 TD1157K30, TD1157K30C, TD1157K30D, TE6957K30A, TK48-57-K30B, TK4857K30C.

How does the repair of the TK52-57K30 work?

Have the fault memory read out, attach the log to the unit and disconnect the battery before you remove the TK52-57K30. Then create the repair order online and pack the unit well before sending it in. At Airbag24, checking, repairing and testing usually takes 3–4 working days.

The sequence is binding for safety reasons, so keep to it exactly.

Airbag24 checks the unit that has been sent in on the test bench, replaces defective components, deletes the crash data and carries out a function test. Then your unit is returned to you. This time applies only to the work at Airbag24. 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 TK52-57K30 get to Airbag24?

You send the control unit TK52-57K30 in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

The printed repair order goes into the parcel, and the unit should be packed shock-proof.