Airbag control unit with part number 28556 1U70A

What does the airbag control unit 28556 1U70A do?

The airbag control unit 28556 1U70A forms the core of the restraint system (SRS) in vehicles of Nissan. It reads the impact sensors, determines in an impact within milliseconds which airbags and seatbelt pretensioners fire, and checks the system continuously. Faults appear via the airbag warning light.

During operation, the unit checks, among other things, whether sensors, cables and output stages are working plausibly. This check runs for as long as the vehicle is switched on.

After an accident, it secures crash data and locks itself.

Why does the control unit 28556 1U70A fail?

Most often the cause is crash data from an accident, even though no airbag fired; an ordinary diagnostic scanner cannot remove it. Ageing components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes from a weak battery or jump starting are also involved.

The crash data is held in the control unit itself, and an ordinary scanner cannot reach it to erase it. A fault can therefore persist even though nothing conspicuous is visible on the vehicle.

The other causes act over a long period. Ageing electronics, fine cracks in solder joints and moisture at the plugs degrade the signals, while voltage fluctuations stress the components.

How can you tell that the 28556 1U70A is defective?

A clear indication is an airbag warning light that stays on permanently or intermittently, together with a fault message in the instrument cluster. If the diagnostic tool cannot access the control unit and the fault memory cannot be cleared, this warning sign is added. In this state, airbags and seatbelt pretensioners may not trigger in an emergency.

Typical signs are:

• instrument cluster warning light that burns constantly
• warning light that comes on only intermittently
• fault message in the instrument cluster
• diagnostic tool cannot establish a connection
• fault memory remains occupied

A message of this kind is a warning, even if the car drives normally. Raise it promptly.

Which vehicles is the 28556 1U70A fitted in?

The airbag control unit 28556 1U70A is fitted in these vehicles: Nissan Note E11 (2005-2007), E11 1st Facelift (2007-2009) and E11 2nd Facelift (2009-2013).

Below are the models that are stored in our information on this control unit.

• Nissan Note E11 (2005-2007)
• Nissan Note E11 1st Facelift (2007-2009)
• Nissan Note E11 2nd Facelift (2009-2013)

Compare the part number on the label of the removed unit with this page; this only confirms that you have the right unit in front of you. Have the fault memory read out in advance, because only this 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 285001909, 98820 BH20A, 98820-3VC0A, 98820-9U10A, 988209U30A.

How does the repair of the 28556 1U70A work?

First read out the fault memory and attach the log. Then disconnect the battery, remove the control unit, create a repair order online and send it in packed. At Airbag24, processing usually takes 3–4 working days.

The order of these steps is fixed for safety reasons and must not be swapped. Only once the log has been secured should you disconnect the battery.

At Airbag24, the unit goes onto the test bench. There, defective components are replaced, the crash data is removed and a functional test is run before your own unit is returned.

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 1U70A get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. Airbag24 sends it back by UPS after the repair. A printed repair order belongs in the parcel, and the unit is packed shock-proof.

Impacts can damage the electronics, so the packaging needs firm material and padding all round.