Airbag control unit with part number 98221AL040

What does the airbag control unit 98221AL040 do?

The SRS control unit 98221AL040 coordinates the restraint system of Subaru. It checks the signals from the crash sensors continuously and, in a collision, decides within milliseconds which airbags and seatbelt pretensioners are triggered.

It also monitors the wiring and components of the system without interruption. If it finds a fault, it stores the fault and shows it via the airbag warning light.

After an accident, the control unit stores crash data and locks itself.

Why does the control unit 98221AL040 fail?

With the 98221AL040, stored crash data from an accident is most often the cause, even if no airbag has been triggered. It cannot be erased with a standard diagnostic tool. Aged components, cold solder joints, moisture at plug connections and voltage spikes also play a part.

The crash data sits in the memory of the unit and stays there until someone removes it.

Electronics age, solder joints can go cold, and moisture attacks plug connections. Voltage spikes, for example from a weak battery or jump-starting, put additional stress on the unit.

How can you tell that the 98221AL040 is defective?

The airbag warning light in the instrument cluster stays on permanently or lights up intermittently. Add to this an error message in the instrument cluster, no connection from the diagnostic tool to the 98221AL040, and a fault memory that cannot be cleared.

The warning light reports the state of the restraint system. If the fault is present, the light stays on or keeps coming back on. A diagnostic tool that cannot establish a connection also points to a fault.

In an emergency, airbags and seatbelt pretensioners may not be able to trigger. Have the findings examined promptly.

Which vehicles is the 98221AL040 fitted in?

The control unit 98221AL040 is fitted in the following vehicles: Subaru Legacy BN (2014-2017), BN Facelift (2017-2020), BS (2014-2017) and BS Facelift (2017-2020); Subaru Outback BS Facelift (2018-2021) and BS (2015-2018). The list is useful for a first check against your vehicle.

These vehicles are known to us for this part number:

• Subaru Legacy BN (2014-2017)
• Subaru Legacy BN Facelift (2017-2020)
• Subaru Legacy BS (2014-2017)
• Subaru Legacy BS Facelift (2017-2020)
• Subaru Outback BS Facelift (2018-2021)
• Subaru Outback BS (2015-2018)

Compare the part number on the label of the removed unit with this page; this shows that it is the right unit. It does not explain the cause, however. Have the fault memory read out first, because only that result shows whether the control unit itself is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 98221AL07A, 98221AN00A, 98221AN00E, 98221AN01A, 98221AN01D, 98221AN10A.

How does the repair of the 98221AL040 work?

First have the fault memory read out and enclose the log. Then disconnect the battery, and only then remove the control unit 98221AL040. Next, create a repair order online and send the well-packed unit in; processing at Airbag24 usually takes 3–4 working days.

At Airbag24 the unit is checked on the test bench, defective components are repaired, stored crash data is erased and a function test is carried out. The 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 98221AL040 get to Airbag24?

You send the control unit 98221AL040 as a parcel. Alternatively, you can book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Enclose the printed repair order in the parcel; the unit must be packed shockproof.