Airbag control unit with part number 28556-3SJ0B

What does the airbag control unit 28556-3SJ0B do?

In Nissan vehicles, the airbag control unit 28556-3SJ0B is the unit that controls the SRS restraint system. It receives the readings from the crash sensors and decides within milliseconds in an accident whether the airbags and seatbelt pretensioners are triggered. It also checks the system constantly and shows faults via the airbag warning light.

If an accident occurs, the unit secures crash data and then locks itself.

In the background, the control unit keeps working quietly. Any faults it detects are stored in the fault memory, which a workshop reads out with a diagnostic tool.

Why does the control unit 28556-3SJ0B fail?

The 28556-3SJ0B most often fails because of crash data from an accident, even if no airbag has deployed; a standard diagnostic tool cannot remove this data. Other causes include aged electronics, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

The crash data stays in the unit until Airbag24 erases it during the repair. It therefore has an effect even when the airbags remained intact.

The other triggers concern the electronics themselves. Components age, solder joints can go cold, moisture and corrosion attack the plugs, and voltage spikes, for example with a weak battery or jump-starting, put strain on the circuitry.

How can you tell that the 28556-3SJ0B is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, indicating a fault in the 28556-3SJ0B. In addition, an error message appears in the instrument cluster, the diagnostic tool cannot reach the control unit, and the fault memory cannot be cleared. In that case, airbags and seatbelt pretensioners may not deploy in an emergency.

The light identifies the fault itself, which is why it is the most important warning sign. If the warning light comes on, have the vehicle checked promptly.

An error message or a fault memory that cannot be cleared is also a sign to look out for.

Which vehicles is the 28556-3SJ0B fitted in?

This airbag control unit 28556-3SJ0B is fitted in these vehicles: Nissan Sylphy B17 (from 2012).

You can take the models from the list below.

• Nissan Sylphy B17 (from 2012)

You should compare the part number on the label of the removed unit with the part number on this page; this confirms that it is the right unit. You should also 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 behind it.

How does the repair of the 28556-3SJ0B work?

For the 28556-3SJ0B, you start by reading out the fault memory and enclose the log with the unit. Afterwards, you disconnect the battery and remove the control unit. Finally, you create the repair order online and send in the well-packed unit.

At Airbag24, the unit is examined on the test bench, defective components are replaced, stored crash data is erased and a function test is carried out. The unit then goes back to you.

Processing usually takes 3–4 working days and 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 28556-3SJ0B get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. The return after the repair is also made by UPS.

The printed repair order goes into the parcel, and you pack the unit shock-proof.