Airbag control unit with part number 89170-42D90

What does the airbag control unit 89170-42D90 do?

The airbag control unit 89170-42D90 coordinates the SRS restraint system in Toyota vehicles. It records the crash signals, decides within milliseconds in a collision whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. Faults appear on the airbag warning light.

The system consists of sensors, wiring, airbags and seatbelt pretensioners, which the control unit monitors together. This keeps the system ready to work in an emergency.

An accident leaves traces in the unit: it stores crash data and locks itself afterwards.

Why does the control unit 89170-42D90 fail?

Most often a control unit fails because of stored crash data left in the unit after an accident, even without an airbag deployment. A normal diagnostic tool cannot delete it. Other causes are ageing components, cold solder joints, moisture and corrosion on plug connectors, and voltage spikes.

Crash data does not reveal itself. In everyday driving you may notice nothing of it until the diagnosis takes place.

The other causes relate to ageing and environmental influences. Electronic components change over time, cold solder joints lead to contact problems, and moisture or corrosion impairs the plugs. Voltage spikes occur, for example, with a weak battery or a jump start.

Airbag24 deletes the crash data during the repair.

How can you tell that the 89170-42D90 is defective?

The airbag warning light in the instrument cluster indicates a defect in the 89170-42D90 when it lights up permanently or intermittently. An error message also appears in the instrument cluster, there is no connection to the diagnostic tool, and the fault memory cannot be cleared. As a result, the airbags and seatbelt pretensioners may fail to deploy in an emergency.

The warning comes directly from the control unit.

If the diagnostic tool cannot establish contact, this likewise means that something needs checking here.

Which vehicles is the 89170-42D90 fitted in?

In this vehicle, the control unit 89170-42D90 from Toyota is fitted: Toyota RAV4 XA50 (from 2018).

You can see the vehicle assignment in the list.

• Toyota RAV4 XA50 (from 2018)

Comparing the part number on the label of the removed unit with this page only ensures that you have the correct unit in front of you. Whether the control unit is defective or a plug or cable is the cause only becomes clear once the fault memory has been read out.

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 89170-42D90 work?

First you read out the fault memory and enclose the log. Then you disconnect the battery and remove the control unit 89170-42D90. After that, you create a repair order online and send in the carefully packed unit.

Airbag24 tests the unit on the test bench, replaces defective components, deletes stored crash data and carries out a function test. The own unit is then returned to you.

Processing at Airbag24 usually takes 3–4 working days.

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 89170-42D90 get to Airbag24?

You send the control unit 89170-42D90 to Airbag24 as a parcel or arrange a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

Enclose the printed repair order with the parcel. Pack the control unit shock-proof.