Airbag control unit with part number 98221SJ420

What does the airbag control unit 98221SJ420 do?

The airbag control unit 98221SJ420 controls the restraint system (SRS) for Subaru. It reads the crash sensors, decides in an accident within milliseconds which airbags and seatbelt pretensioners to trigger, and monitors the system continuously. It shows faults via the airbag warning light.

The sensors are distributed throughout the vehicle and report their readings to the control unit continuously. The assessment takes place there, so that only an actual impact leads to a trigger.

After an accident, the unit writes crash data to its memory and then locks itself. This memory records the event.

Why does the control unit 98221SJ420 fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered. They cannot be erased with a normal diagnostic tool. Other causes are aged components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes from a battery that is weak or a jump-start.

Crash data is not obvious on the vehicle itself as long as it drives inconspicuously.

The other causes at a glance:

• age-related damage to electronic components
• cold solder joints
• moisture and corrosion on plug connections
• voltage spikes arising from a weak battery or a jump-start

How can you tell that the 98221SJ420 is defective?

The airbag warning light in the instrument cluster lights up constantly or intermittently, and a defect in the 98221SJ420 may also show up as an error message. The diagnostic tool may then find no contact with the control unit, and the fault memory cannot be cleared. In a crash, the airbags and seatbelt pretensioners may possibly not trigger.

Anyone who takes the warning light seriously has the system checked promptly.

Which vehicles is the 98221SJ420 fitted in?

The 98221SJ420 is fitted in these vehicles: Subaru Forester SK (2018-2021) and SK Facelift (from 2021).

Below are the vehicles that match this part number.

• Subaru Forester SK (2018-2021)
• Subaru Forester SK Facelift (from 2021)

Check in advance whether the part number on the label of your unit matches this page. That only proves that it is the right unit, nothing more. Whether the control unit is defective or a plug or cable is responsible is shown by the fault memory, which you have read out beforehand.

For the same vehicles, we also repair control units with the part numbers 1523004370, 98221FC210, 98221SJ000, 98221SJ001.

How does the repair of the 98221SJ420 work?

You have the fault memory read out, keep the log and disconnect the battery before you remove the 98221SJ420. Then you create the repair order online and send in the well-packed unit. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 examines the unit on the test bench, replaces defective parts, erases the crash data and tests the function. Your own unit is then 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 98221SJ420 get to Airbag24?

Either you send the unit in as a parcel, or you arrange a UPS collection for an extra charge. After the repair, Airbag24 sends the 98221SJ420 back by UPS. Put the printed repair order into the parcel.

Make sure the packaging is shock-proof so that the unit survives transport.