Airbag control unit with part number 28556-4JF0B

What does the airbag control unit 28556-4JF0B do?

The airbag control unit 28556-4JF0B is the central control unit of the restraint system (SRS) in Nissan. It evaluates the crash sensors, determines the triggering of airbags and seatbelt pretensioners in an accident and monitors the system continuously. Faults are displayed via the airbag warning light.

The unit works in the background and constantly checks whether all connected components deliver plausible values. Deviations end up in the fault memory.

After an accident, the control unit stores crash data and then locks itself. It therefore also serves as the memory for accident data.

Why does the control unit 28556-4JF0B fail?

The most common cause is crash data stored after an accident, even if no airbag has fired. A standard diagnostic tool does not remove it. Aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes are also possible causes.

The memory therefore remains occupied even when the vehicle has long been back on the road.

The other causes develop gradually. Corrosion on a connector builds up step by step, and voltage spikes arise, for example, from a weak battery or from jump-starting.

How can you tell that the 28556-4JF0B is defective?

A defect shows up as the airbag warning light, which lights up permanently or intermittently, as error messages in the instrument cluster, or as a fault memory that cannot be cleared. In an emergency, the airbags and seatbelt pretensioners may then fail to deploy.

The signs can occur individually or together:

• airbag warning light in the instrument cluster stays on permanently
• airbag warning light comes on only intermittently
• error message in the instrument cluster
• diagnostic tool does not connect to the control unit
• fault memory cannot be cleared

The light indicates a condition that must be checked.

Which vehicles is the 28556-4JF0B fitted in?

The control unit 28556-4JF0B is fitted in these vehicles: Nissan Navara D40 (2005-2007) and D40 Facelift (2007-2015). Which models match exactly is shown by comparing the part number with the vehicle.

The list covers the models for which this part number is recorded:

• Nissan Navara D40 (2005-2007)
• Nissan Navara D40 Facelift (2007-2015)

On the one hand, compare the part number on the label of the removed unit with this page; this ensures that you have the right unit. On the other hand, have the fault memory read out. Only then is it clear whether the control unit is defective or whether a connector or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 285001734, 28556 4X00A, 28556EA100, 98820 5X20B, 98820 EB01C, 98820 EB01D.

How does the repair of the 28556-4JF0B work?

First have the fault memory read out, attach the log to the unit and disconnect the battery; only then remove the control unit 28556-4JF0B. Next, create a repair order online and send the unit in well packed. Testing, repairing and checking at Airbag24 take 3–4 working days as a rule.

Keep to this order even if removal would be quick, because it serves your safety.

At Airbag24, the unit is placed on the test bench, defective components are rectified, stored crash data is erased and a function test is carried out. The unit then returns 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 28556-4JF0B get to Airbag24?

You send the unit as a package or book a UPS collection for an extra charge. After the repair, Airbag24 sends the control unit 28556-4JF0B back to you by UPS.

Enclose the printed repair order and pack the control unit 28556-4JF0B shock-proof.