Airbag control unit with part number 28556 EV20A

What does the airbag control unit 28556 EV20A do?

The airbag control unit 28556 EV20A is the central control unit of the restraint system (SRS) for Nissan. It evaluates the signals from the crash sensors and decides in an accident within milliseconds which airbags and seatbelt pretensioners are triggered. After an accident, it stores crash data and locks itself.

In everyday use the unit monitors the entire system continuously. If it detects a fault, it shows it via the airbag warning light in the instrument cluster, and the display remains until the fault is rectified.

The lock is only lifted by the repair. The fact that the control unit locks itself is therefore the point that matters most to you as the vehicle keeper.

Why does the control unit 28556 EV20A fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered. A normal diagnostic tool cannot erase this data. Other possible causes are aged electronic components, dry solder joints, moisture and corrosion at plug connections, and voltage spikes.

That no airbag was triggered does not mean that no crash data was stored. Nothing of this can be seen on the vehicle from the outside, so the cause is found in the fault memory and not on the housing.

• Aged electronic components
• Dry solder joints
• Moisture and corrosion at plug connections
• Voltage spikes, for example with a weak battery or a jump start

Which of these causes applies in an individual case is only shown by the test on the test bench.

How can you tell that the 28556 EV20A is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and a fault message appears in the instrument cluster. The diagnostic tool does not get a connection to the control unit, and the fault memory cannot be cleared.

As long as these signs persist, airbags and seatbelt pretensioners may not trigger in an emergency. The defect is therefore indicated, and the light is a clear hint that you must not ignore.

Anyone who sees the message should have the system checked promptly.

Which vehicles is the 28556 EV20A fitted in?

The control unit 28556 EV20A is fitted in these vehicles: Nissan 350Z Z33 1st Facelift (2005-2007) and Z33 2nd Facelift (2007-2009).

The individual vehicles for which this unit is intended are listed here:

• Nissan 350Z Z33 1st Facelift (2005-2007)
• Nissan 350Z Z33 2nd Facelift (2007-2009)

Compare the part number on the label of the removed unit with this page. That only ensures that you have the correct unit in front of you. Also have the fault memory read out in advance, because only this result shows whether the control unit itself is defective or whether a plug or a cable is the cause.

For the same vehicles, we also repair control units with the part numbers 98820CD600.

How does the repair of the 28556 EV20A work?

For the repair of the 28556 EV20A, you first read out the fault memory and enclose the log. Then you disconnect the battery and only afterwards remove the control unit. Next, you create a repair order online and send in the well-packed unit.

Airbag24 checks the unit on the test bench, replaces defective components, erases stored crash data and carries out a function test. Afterwards the unit goes back to you.

Processing at Airbag24 typically takes 3–4 working days.

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 EV20A get to Airbag24?

You send the control unit 28556 EV20A in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS.

Put the printed repair order into the parcel and pack the control unit in a shock-resistant way.