Airbag control unit with part number 28556-3SU0A

What does the airbag control unit 28556-3SU0A do?

The airbag control unit 28556-3SU0A 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 whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. It reports faults via the airbag warning light.

In everyday use the control unit works unobtrusively in the background. It checks the connections to sensors, airbags and seatbelt pretensioners and sends irregularities to the instrument cluster.

After an accident, it stores crash data and locks itself. This affects the entire restraint system, because the control unit is its central switching point.

Why does the control unit 28556-3SU0A fail?

The most common cause for the 28556-3SU0A is crash data stored after an accident, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Other possible causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, such as those from a weak battery or a jump start.

Crash data remains in the memory after an accident, even if no airbag has fired. At Airbag24 it is erased during the repair.

The other causes mainly concern the electronics themselves. Components age, solder joints can become cold, and moisture or corrosion attack plug connections. Which cause applies only becomes clear through the investigation.

How can you tell that the 28556-3SU0A is defective?

A defect in the 28556-3SU0A shows up through the airbag warning light, fault messages in the instrument cluster, or a diagnostic tool that cannot reach the control unit. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

• The airbag warning light in the instrument cluster stays on permanently.
• The light comes on only intermittently.
• A fault message regarding the airbag system appears in the instrument cluster.
• The diagnostic tool cannot find the control unit.
• The fault memory cannot be erased.

Have a lit warning light checked promptly, even if the vehicle can still be driven normally.

Which vehicles is the 28556-3SU0A fitted in?

The control unit 28556-3SU0A is fitted in these vehicles: Nissan Sylphy B17 (from 2012).

The vehicles in detail:

• Nissan Sylphy B17 (from 2012)

First 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. Then have the fault memory read out, because only this result shows whether the control unit is defective or whether a plug or a cable is the cause.

How does the repair of the 28556-3SU0A work?

For the 28556-3SU0A, first have the fault memory read out and enclose the log before you disconnect the battery and remove the control unit. Then create the repair order online and send the well-packed unit in. At Airbag24, checking, repairing and testing usually take 3–4 working days.

The sequence is fixed for safety reasons. Only once the battery is disconnected is the control unit removed.

On the test bench the unit is checked. Where necessary, defective components are repaired, the stored crash data is erased and a function test is carried out. Afterwards, 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 28556-3SU0A get to Airbag24?

You send the control unit 28556-3SU0A as a parcel, or you book a UPS collection for an extra charge. After repair, Airbag24 returns it by UPS.

Enclose the printed repair order in the parcel. The control unit must be packed shockproof.