Airbag control unit with part number 98820-5SY0B

What does the airbag control unit 98820-5SY0B do?

The airbag control unit 98820-5SY0B is the central component of the restraint system (SRS) in Nissan. Signals from the crash sensors converge there; from them it works out within fractions of a second which airbags and seatbelt pretensioners to fire. After an accident it stores crash data and locks itself; only a repair lifts the lock.

The unit checks the system continuously and reports irregularities via the airbag warning light in the instrument cluster.

It works in the background all the time, even when you notice nothing of it.

Why does the control unit 98820-5SY0B fail?

Crash data from an accident stored in the unit cause the failure most often, even when no airbag has fired; ordinary diagnostic tools cannot erase them. Ageing components, cold solder joints, moisture and corrosion on the plugs, and voltage spikes also play a part.

Stored crash data remain as an entry in the control unit, even if the vehicle carries on afterwards without visible damage. Reading the data out shows that they are present, but erasing them does not succeed that way.

Ageing electronics, cold solder joints and moisture are typical causes inside the unit, because they weaken the connections. Voltage spikes occur, for example, with a weak battery or when jump-starting, and they put the electronics under strain.

How can you tell that the 98820-5SY0B is defective?

The airbag warning light in the instrument cluster indicates the fault when it lights up permanently or intermittently. Fault messages in the instrument cluster and a fault memory that cannot be cleared add to this. Airbags and seatbelt pretensioners may then possibly not fire in an emergency.

Look out for these signs:

• Airbag warning light permanently or intermittently on
• Fault message in the instrument cluster
• Fault memory cannot be cleared
• Diagnostic tool gets no connection to the control unit

Several of these signs at the same time justify a check, even if the car still drives.

Which vehicles is the 98820-5SY0B fitted in?

The control unit 98820-5SY0B is fitted in these vehicles: Nissan Leaf ZE1 (from 2017).

The list shows the models for which this control unit is recorded.

• Nissan Leaf ZE1 (from 2017)

Check the part number on the label of the removed unit and compare it with this page; this only confirms that the unit matches. Whether the control unit is defective or a plug or cable is behind the fault is shown only by the fault memory read out in advance.

For the same vehicles, we also repair control units with the part numbers 98820-4NS0A, 98820-4NS9A, 98820-5SA0E.

How does the repair of the 98820-5SY0B work?

The repair of the 98820-5SY0B begins with reading out the fault memory, and you enclose the log with the unit. Then you disconnect the battery and remove the control unit. After that you create a repair order online; Airbag24 generally needs 3–4 working days for checking, repairing and testing.

At Airbag24 the unit is examined on the test bench. Defective components are repaired, stored crash data are erased and a final function test is carried out. Then your own unit is sent back 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 98820-5SY0B get to Airbag24?

You send in the control unit 98820-5SY0B as a parcel or, for an extra charge, book a UPS collection; after the repair Airbag24 returns it by UPS.

The printed repair order goes into the parcel, and the unit must be packed in shock-proof packaging.