Airbag control unit with part number 28556-4CJ0A

What does the airbag control unit 28556-4CJ0A do?

The airbag control unit 28556-4CJ0A forms the control centre of the restraint system (SRS) in the Nissan. It processes the measurements from the crash sensors and decides in a crash, within a few milliseconds, which airbags and seatbelt pretensioners are triggered.

It also checks the wiring and the firing circuits continuously for faults. Detected faults are shown via the airbag warning light in the instrument cluster. After an accident, the control unit stores crash data and locks itself.

Why does the control unit 28556-4CJ0A fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Other causes come into consideration as well.

A unit with crash data shows faults that cannot be cleared with standard tools.

• aged electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes, for example from a weak battery or jump start

How can you tell that the 28556-4CJ0A is defective?

The airbag warning light in the instrument cluster lights up constantly or intermittently, an error message appears, the diagnostic tool cannot reach the control unit, or the fault memory cannot be cleared. In a critical situation, the airbags and seatbelt pretensioners may then not be able to deploy.

The warning light reports a fault directly, and it therefore counts among the most important warning signs. If it stays lit after the ignition is switched on, a fault is present and reading out the fault memory becomes necessary.

Which vehicles is the 28556-4CJ0A fitted in?

The control unit 28556-4CJ0A is fitted in these vehicles: Nissan X-Trail T32 (2014-2017) and T32 Facelift (2017-2022).

These models are on record for this part number:

• Nissan X-Trail T32 (2014-2017)
• Nissan X-Trail T32 Facelift (2017-2022)

Compare the part number on the label of the removed unit with this page to confirm that it is the correct unit. Have the fault memory read out beforehand, because only the result shows whether the control unit itself is defective or whether a connector or a cable is the cause.

For the same vehicles, we also repair control units with the part numbers 1520831000, 152083100B, 1520831U00, 1520831U01, 1520831U0A, 98820JH43A.

How does the repair of the 28556-4CJ0A work?

First have the fault memory read out and attach the log. Then disconnect the battery and remove the control unit. Afterwards create a repair order online and send the well-packed unit in. Checking, repairing and testing usually takes 3–4 working days at Airbag24.

The sequence is fixed for safety reasons: read out first, then disconnect the battery, then remove the unit.

At Airbag24 the unit is checked on the test bench. Defective components are replaced, crash data is erased, and a function test is carried out. 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 28556-4CJ0A get to Airbag24?

You send the control unit 28556-4CJ0A as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Put the printed repair order in the parcel and pack the unit shockproof.