Airbag control unit with part number 28556-4KK0C

What does the airbag control unit 28556-4KK0C do?

The airbag control unit 28556-4KK0C is the central control unit of the restraint system (SRS) for Nissan. It evaluates the signals from the crash sensors, decides in an accident within milliseconds which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

If the unit detects a fault, it displays this via the airbag warning light in the instrument cluster. This way you notice in everyday use that something is wrong with the restraint system.

The sensors for impact and acceleration are connected via wiring harnesses. The evaluation runs in the background; you do not need to operate or adjust anything for it.

After an accident, the control unit stores crash data and locks itself. This lock is not shown in the vehicle as a separate indication, but when the fault memory is read out with the diagnostic tool.

Why does the control unit 28556-4KK0C fail?

The most common cause is crash data stored after an accident, even if no airbag has triggered. Besides the crash data, ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes are possible causes.

Crash data cannot be erased with an ordinary diagnostic tool. They therefore remain stored in the control unit, and that is exactly how you can recognise that an accident may be the cause.

The other causes concern the electronics and the connections inside the unit:

• ageing electronic components
• cold solder joints on the circuit board
• moisture and corrosion at plug connections
• voltage spikes, for example from a weak battery or when a jump start is connected

How can you tell that the 28556-4KK0C is defective?

The airbag warning light in the instrument cluster lights up constantly or only intermittently. In addition, an error message appears in the instrument cluster, the diagnostic tool receives no connection to the control unit, and the fault memory cannot be cleared. If these signs occur, airbags and seatbelt pretensioners may not trigger in an emergency.

That the light only comes on intermittently does not mean the system is fine. The control unit indicates a detected fault via the light, and you should take this indication seriously.

If no connection to the diagnostic tool can be established, this may point to the control unit itself, but it need not. Whether the unit is affected is shown only by reading out the fault memory.

Which vehicles is the 28556-4KK0C fitted in?

The control unit 28556-4KK0C is fitted in these vehicles: Nissan Frontier D23 (2015-2020); Nissan Navara D23 (2015-2020).

For orientation, we list the models for which this control unit is stored in our data.

• Nissan Frontier D23 (2015-2020)
• Nissan Navara D23 (2015-2020)

On the one hand, compare the part number on the label of the removed unit with this page. This only ensures that you have the right unit in front of you. On the other hand, have the fault memory read out before removal, because only this result shows whether the control unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 0 285 015 304, 28556-8Z325, 285569Z510, 28556EA10A, 98820 6KB0A, 98820 EB01D.

How does the repair of the 28556-4KK0C work?

First have the fault memory read out and attach the log, then disconnect the battery and only then remove the control unit. Afterwards create a repair order online and send the unit in well packed. At Airbag24, checking, repairing and testing usually take 3–4 working days.

The order of these steps is mandatory for safety reasons. The control unit may only be removed once the battery has been disconnected.

At Airbag24, the unit is examined on the test bench. Defective components are replaced, stored crash data are erased, and a function test is then carried out. Afterwards your own, repaired 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 28556-4KK0C get to Airbag24?

You send the control unit in as a parcel, or you arrange a UPS collection for an extra charge. After the repair, Airbag24 sends the unit back to you by UPS.

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