Airbag control unit with part number 89170-42D31

What does the airbag control unit 89170-42D31 do?

The airbag control unit 89170-42D31 controls the restraint system (SRS) for Toyota. In a crash it checks the signals from the crash sensors and decides within milliseconds whether airbags and seatbelt pretensioners are triggered.

During operation it monitors the entire system and shows faults via the airbag warning light in the instrument cluster.

After an accident it stores crash data and then locks itself.

Why does the control unit 89170-42D31 fail?

The most common cause is crash data left in the unit after an accident, even if no airbag was triggered. A standard diagnostic tool cannot erase this data. Other causes include ageing components, cold solder joints, moisture and voltage spikes.

Crash data remains in the memory until it is removed during the repair. You cannot remove it yourself by usual means, because of the way it is stored.

The other causes concern the electronics. Components age, solder joints can go cold, and moisture or corrosion attack plug contacts.

How can you tell that the 89170-42D31 is defective?

The airbag warning light in the instrument cluster stays on permanently or intermittently, a fault message appears, the diagnostic tool finds no connection to the control unit, or the fault memory cannot be cleared.

• airbag warning light in the instrument cluster
• fault message in the instrument cluster
• missing connection between diagnostic tool and control unit
• fault memory that cannot be cleared

In an emergency, airbags and seatbelt pretensioners may fail to trigger with such a defect.

Which vehicles is the 89170-42D31 fitted in?

The control unit 89170-42D31 is fitted in these vehicles: Toyota RAV4 XA50 (from 2018).

The list shows the vehicles recorded for this part number.

• Toyota RAV4 XA50 (from 2018)

Check whether the part number on the label of the removed unit matches this page. That only tells you that it is the right unit. Have the fault memory read out beforehand, because only the log 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 150800-4431, 152100-0262, 152100-4560, 89170-42400, 89170-42870, 89170-42A60.

How does the repair of the 89170-42D31 work?

First have the fault memory read out and attach the log. Then disconnect the battery and remove the control unit. Create the repair order online and send in the well-packed unit. Processing at Airbag24 usually takes 3–4 working days.

Airbag24 checks the unit on the test bench, replaces defective components, erases stored crash data and carries out a function test. The 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 89170-42D31 get to Airbag24?

You send the unit as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 sends it back via UPS.

Put the printed repair order in the parcel and pack the unit shock-resistant.