Airbag control unit with part number 28556-3TP0A

What does the airbag control unit 28556-3TP0A do?

The airbag control unit 28556-3TP0A is the central unit of the restraint system (SRS) at Nissan. It evaluates the signals from the impact sensors, decides in a crash whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. After an accident it stores crash data and locks itself.

If the unit detects a fault, it reports it via the airbag warning light in the instrument cluster.

The firing circuits of the airbags and seatbelt pretensioners are among the parts checked continuously.

Why does the control unit 28556-3TP0A fail?

The most common cause is crash data stored in the memory after an accident, even if no airbag fired; an ordinary diagnostic tool cannot erase it. Other causes include ageing electronics, moisture, corrosion and voltage spikes.

• Wear and ageing of electronic components
• Cold solder joints
• Moisture and corrosion at plug connections
• Voltage spikes, for example from a weak battery

Airbag24 erases the crash data during the repair.

How can you tell that the 28556-3TP0A is defective?

When the airbag warning light in the instrument cluster lights up permanently or intermittently and a fault message appears, a defect in the 28556-3TP0A is likely. The diagnostic tool then has no connection, and the fault memory cannot be cleared. In a crash, airbags and seatbelt pretensioners may then fail to fire.

Such an indication calls for a check of the system.

Which vehicles is the 28556-3TP0A fitted in?

The control unit 28556-3TP0A is fitted at Nissan in these models: Nissan Altima L33 (2012-2018).

Below is the list of models.

• Nissan Altima L33 (2012-2018)

Comparing the part number on the label of the removed unit with this page is a sensible step that only confirms the unit's identity. Whether the control unit itself or a cable or plug is the cause is shown only by reading the fault memory before removal.

For the same vehicles, we also repair control units with the part numbers 98820-3TA0B, 98820-3TA9C, 98820-9HN0A, 98820-9HS9A.

How does the repair of the 28556-3TP0A work?

First the fault memory is read out, and the log goes into the parcel. Then disconnect the battery and only then remove the control unit 28556-3TP0A. In the last step create a repair order online and send the well-packed unit.

At Airbag24 the unit goes on the test bench, and defective components are replaced. Airbag24 removes the stored crash data before a functional test follows, and your own unit returns.

Processing usually takes 3–4 working days; this period covers checking, repairing and testing. 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 28556-3TP0A get to Airbag24?

You send the control unit 28556-3TP0A as a parcel, or book a UPS collection for an extra charge. After the repair it returns to you by UPS.

Enclose the printed repair order in the parcel, with shockproof packaging.