Airbag control unit with part number 28556-3TP0B

What does the airbag control unit 28556-3TP0B do?

The 28556-3TP0B is the central control unit of the restraint system (SRS) for Nissan. It evaluates the crash sensors, decides within milliseconds whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

The unit reports faults via the airbag warning light in the instrument cluster. At the same time it stores the fault in the fault memory, so that it remains traceable later.

After an accident the control unit stores crash data and locks itself. You notice this state at every diagnosis first, because the unit then reacts differently than before.

Why does the control unit 28556-3TP0B fail?

The most common cause is crash data stored after an accident, even if no airbag has fired; a normal diagnostic tool cannot erase it. Further causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data remains stored even if no airbag fired in the accident. An ordinary diagnostic tool cannot reach it. During the repair at Airbag24 the data is erased, followed by the check of the other assemblies.

The other causes are of a more gradual nature. Electronics age, solder joints can go cold, and moisture with corrosion attacks plug connections. Voltage spikes, for example from a weak battery or a jump-start, additionally load the unit.

How can you tell that the 28556-3TP0B is defective?

The airbag warning light lights up continuously or intermittently, a fault message appears in the instrument cluster, the diagnostic tool finds no connection to the control unit, or the fault memory cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then fail to deploy.

The warning light in particular is the most important warning sign you see in the vehicle. It indicates a fault as soon as the unit detects one, and it should therefore be taken seriously.

If the diagnostic tool cannot establish a connection, the cause is not always the control unit itself. Only reading out the fault memory clarifies this.

Which vehicles is the 28556-3TP0B fitted in?

The 28556-3TP0B is fitted in these vehicles: Nissan Altima L33 (2012-2018).

The following list shows the vehicles recorded for this part number.

• Nissan Altima L33 (2012-2018)

Please note the following. Compare the part number on the label of the removed unit with this page; this only confirms that it is the correct unit. Also have the fault memory read out beforehand. Only the 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 98820-3TA0B, 98820-3TA9C, 98820-9HN0A, 98820-9HS9A.

How does the repair of the 28556-3TP0B work?

First have the fault memory read out and enclose the log, then disconnect the battery and only then remove the 28556-3TP0B. Then create the repair order online and send in the well-packed unit. Processing at Airbag24 usually takes 3–4 working days.

The order of the first steps is fixed, because it makes the removal safer. The log goes into the parcel so that the testing can build on the finding from the start.

After the functional test 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 28556-3TP0B get to Airbag24?

You send the 28556-3TP0B in as a parcel or book a UPS collection for an extra charge; after the repair Airbag24 sends it back to you by UPS.

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