Airbag control unit with part number 98221SJ020

What does the airbag control unit 98221SJ020 do?

The airbag control unit 98221SJ020 controls the restraint system (SRS) of Subaru. It evaluates the signals from the crash sensors, determines in an accident within fractions of a second which airbags and seatbelt pretensioners are triggered, and reports faults via the airbag warning light.

In the background the unit continuously checks the entire trigger chain, from the sensors through the wiring to the airbag output stages. If it detects a deviation, it creates a fault entry and shows it in the instrument cluster.

After an accident the control unit stores crash data and locks itself. Because it belongs to the safety system, every intervention calls for particular care.

Why does the control unit 98221SJ020 fail?

The most common cause on the 98221SJ020 is crash data from an accident, even if no airbag was triggered; a normal diagnostic tool cannot delete it. Other possible causes are aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

The crash data is held in the unit itself and cannot be removed with conventional tools.

Aged components and cold solder joints disturb the signal path because the electrical contact weakens. Moisture and corrosion attack the plug connectors.

Voltage spikes arise, for example, from a weak battery or a jump start and can additionally load the electronics.

How can you tell that the 98221SJ020 is defective?

A defect on the 98221SJ020 shows up as the airbag warning light in the instrument cluster lighting up permanently or intermittently. Added to this may be an error message in the instrument cluster, no connection between the diagnostic tool and the control unit, and a fault memory that cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then fail to trigger.

Typical signs at a glance:

• airbag warning light on permanently or intermittently
• error message in the instrument cluster
• diagnostic tool cannot establish a connection to the control unit
• fault memory cannot be cleared

If any of these signs appears, a prompt check is worthwhile. The warning light reports the fault itself.

Which vehicles is the 98221SJ020 fitted in?

The assignment lists the Subaru models in which the unit was installed. The 98221SJ020 is fitted in these vehicles: Subaru Forester SK (2018-2021) and SK Facelift (from 2021).

These vehicles are recorded in the assignment:

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

Before you remove anything, note the following points: a) Compare the part number on the label of the removed unit with this page. This only ensures that it is the correct unit. b) Have the fault memory read out beforehand. Only that 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 1523004370, 98221FC210, 98221SJ000, 98221SJ001.

How does the repair of the 98221SJ020 work?

First read out the fault memory and enclose the log, then disconnect the battery and only then remove the 98221SJ020. Next, create a repair order online and send the unit in well packed. At Airbag24, checking, repairing and testing usually take 3–4 working days.

At Airbag24 the unit is examined on the test bench. Defective components are replaced, stored crash data is deleted, and then a function test follows. Afterwards your own unit goes 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 98221SJ020 get to Airbag24?

You send the 98221SJ020 in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns the unit to you by UPS.

Put the printed repair order into the parcel and pack the control unit shock-proof.