Airbag control unit with part number 28556 3N705

What does the airbag control unit 28556 3N705 do?

The airbag control unit 28556 3N705 coordinates the restraint system (SRS) in the Nissan vehicle. It reads the crash sensors, determines in an emergency within milliseconds which airbags and seatbelt pretensioners fire, and checks the system continuously. After an accident, it stores crash data and locks itself; only the repair lifts the lock.

The unit shows irregularities in the system via the airbag warning light in the instrument cluster. The electronics work constantly in the background, without you noticing anything.

The unit is therefore far more than a component that only becomes active in a collision.

Why does the control unit 28556 3N705 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 are aged components, cold solder joints, moisture and voltage peaks.

The unit keeps crash data in its own memory. Reading it out makes the data visible but does not remove it, which is why the message remains.

Other possible triggers include:

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

How can you tell that the 28556 3N705 is defective?

The airbag warning light in the instrument cluster indicates a fault when it stays on permanently or intermittently. Error messages in the instrument cluster and a fault memory that cannot be cleared are further signs. Then airbags and seatbelt pretensioners may possibly fail to trigger in an emergency.

Watch for these signs:

• airbag warning light on permanently or intermittently
• error message in the instrument cluster
• diagnostic tool receives no connection to the control unit
• fault memory cannot be cleared

The light indicates the finding as soon as the control unit detects it. Several of these signs at once justify a check, even if the vehicle is still driving.

Which vehicles is the 28556 3N705 fitted in?

The control unit 28556 3N705 is fitted in these vehicles: Nissan Almera N15 (1995-1998) and N15 Facelift (1998-2000).

The list is for comparison with your own vehicle.

• Nissan Almera N15 (1995-1998)
• Nissan Almera N15 Facelift (1998-2000)

Compare the part number on the label of the removed unit with this page, so you know it is the right unit. Also have the fault memory read out, because only the result shows whether the control unit is defective or a cable or plug is the cause.

For the same vehicles, we also repair control units with the part numbers 285561N900, 98584-2N400, 9882031805Y, T6595925AA.

How does the repair of the 28556 3N705 work?

First have the fault memory read out and attach the log. Then disconnect the battery and remove the control unit 28556 3N705. Then create a repair order online; Airbag24 needs 3–4 working days for testing, repair and function test as a rule.

You send the well-packed unit in. Airbag24 tests it on the test bench, repairs defective components, erases the stored crash data and carries out a function test. Your own unit goes back afterwards.

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 3N705 get to Airbag24?

You can send the control unit 28556 3N705 in as a parcel or book a UPS collection for an extra charge. Airbag24 returns it by UPS after the repair.

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