Airbag control unit with part number 98221SJ520

What does the airbag control unit 98221SJ520 do?

The airbag control unit 98221SJ520 controls the airbags and seatbelt pretensioners in the restraint system (SRS) of Subaru. Based on the signals from the crash sensors, it decides within milliseconds in an accident on triggering. After an accident, it stores crash data and locks itself; the lock is lifted only by the repair.

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

The electronics are designed so that evaluation takes place without delay in an emergency.

Why does the control unit 98221SJ520 fail?

Most often the cause is crash data stored after an accident, even without a triggered airbag; these cannot be erased with a diagnostic tool. Further causes are aged electronics, cold solder joints, moisture and corrosion at plug connectors, and voltage peaks.

The crash data are the reason why the problem cannot be fixed simply by reading out the fault memory. The erasure takes place only at Airbag24.

Further causes 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 98221SJ520 is defective?

A defect shows up through the airbag warning light in the instrument cluster, which stays on permanently or intermittently, and through an error message. A fault memory that cannot be cleared, or a diagnostic tool without contact to the control unit, indicate a defect. Airbags and seatbelt pretensioners may then possibly fail to trigger in an emergency.

The airbag warning light is the first sign you will notice. It lights up as soon as the electronics detect a fault, and it either stays on or keeps coming back.

An error message in the instrument cluster, a fault memory without a clearing option and a missing contact with the diagnostic tool add to this picture. Each of these signs indicates that the electronics are no longer working properly.

Which vehicles is the 98221SJ520 fitted in?

The control unit 98221SJ520 is fitted in these vehicles: Subaru Forester SK (2018-2021) and SK Facelift (from 2021).

Use this overview to compare with your own vehicle.

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

Compare the part number on the label of the removed unit with this page; this ensures that it is the right unit. Have the fault memory read out in addition, because only the result shows whether the control unit is defective or 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 98221SJ520 work?

Have the fault memory read out first and attach the log. Then disconnect the battery and remove the control unit 98221SJ520. Then create the repair order online and send the unit in, well packed.

Airbag24 tests the unit on the test bench, repairs defective components, erases the stored crash data and carries out a function test. Processing at Airbag24 usually takes 3–4 working days. Your own unit then 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 98221SJ520 get to Airbag24?

You send the control unit 98221SJ520 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

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