Airbag control unit with part number 98221AJ040

What does the airbag control unit 98221AJ040 do?

The airbag control unit 98221AJ040 takes over control of the restraint system (SRS) in Subaru. It checks the signals from the crash sensors, decides in an accident whether airbags and seatbelt pretensioners are triggered, and monitors the overall system. It shows faults via the airbag warning light.

The evaluation runs in the background without pause, because an airbag only protects if it deploys at the right moment. To this end, the measured values are compared with stored limit values.

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

Why does the control unit 98221AJ040 fail?

The most common cause is crash data that remains stored after an accident, even without an airbag having deployed. A normal diagnostic tool cannot remove it. Other triggers are ageing electronics, cold solder joints, moisture at plug connections and voltage spikes.

This data stays in the unit even if nothing was visible from outside, and this is why the fault persists.

The other causes concern the electronics and their connections. These include ageing, cold solder joints on the circuit board, moisture and corrosion, and voltage spikes, for example from a weak battery or a jump start.

How can you tell that the 98221AJ040 is defective?

A defect shows up as the airbag warning light, which lights up permanently or intermittently, and as fault messages in the instrument cluster. In addition, the diagnostic tool cannot connect to the control unit, and the fault memory cannot be cleared.

Typical signs are:

• Airbag warning light, permanently or intermittently
• Fault message in the instrument cluster
• Diagnostic tool without connection to the control unit
• Fault memory remains

In an emergency, airbags and seatbelt pretensioners may then not deploy, so a prompt check is worthwhile.

Which vehicles is the 98221AJ040 fitted in?

The assignment applies to Subaru. The control unit 98221AJ040 is fitted in these vehicles: Subaru Legacy BM (2009-2014) and BR (2009-2014); Subaru Outback BR (2009-2014).

These vehicles are stored in the data set:

• Subaru Legacy BM (2009-2014)
• Subaru Legacy BR (2009-2014)
• Subaru Outback BR (2009-2014)

Compare the label of the removed unit with this page to confirm the correct unit. Have the fault memory read out beforehand, because only this log shows whether the control unit itself is affected or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 150300-2150, 150300-2151, 150300-4650, 150300-4670, 98221AE040, 98221AG260.

How does the repair of the 98221AJ040 work?

First have the fault memory read out and enclose the log. Then disconnect the battery and remove the control unit. Only afterwards create the repair order online, and then send the unit in well packed. Processing at Airbag24 usually takes 3–4 working days.

At Airbag24 the unit is inspected on the test bench. Defective components are replaced, the crash data is deleted and a functional test is carried out.

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 98221AJ040 get to Airbag24?

You send the unit as a parcel or book UPS collection for an extra charge. UPS takes care of the return once Airbag24 has finished the unit.

Pack the unit shock-resistant, and enclose the printed repair order.