Airbag control unit with part number 89170-0C590

What does the airbag control unit 89170-0C590 do?

The airbag control unit 89170-0C590 is the central control unit of the restraint system (SRS) for Toyota. It evaluates the signals of the crash sensors and, in an accident, decides within milliseconds which airbags and seatbelt pretensioners are triggered. After an accident it stores crash data and locks itself.

The control unit monitors the system constantly. Faults it finds are indicated via the airbag warning light in the instrument cluster.

While driving, you are not aware of it. Its work is limited to evaluating the sensors and controlling the restraint devices.

Why does the control unit 89170-0C590 fail?

The most common cause is stored crash data, even if no airbag was triggered in the accident. A normal diagnostic tool cannot delete these data, and Airbag24 deletes them during the repair. Other causes are ageing electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes, for example from a weak battery.

After an impact, the control unit creates crash data, and they remain until they are removed during a repair. This applies regardless of whether an airbag has actually been triggered.

The other causes are mostly everyday ageing and weathering of the contacts. A loose or corroded connection can cause a failure just as a component that weakens over the years can.

How can you tell that the 89170-0C590 is defective?

A defect shows itself through the airbag warning light in the instrument cluster, which stays on permanently or intermittently, and through an error message in the instrument cluster. The diagnostic tool then finds no connection to the control unit, and the fault memory cannot be cleared. Airbags and seatbelt pretensioners may then fail to trigger in an emergency.

The warning light shows the state of the system directly in your field of view. If it stays on permanently or flickers intermittently, that is a clear sign to have the fault memory read out.

Plugs and wiring can show the same symptoms as the unit itself. That is why only reading out the fault memory brings clarity about the affected point.

Which vehicles is the 89170-0C590 fitted in?

The control unit 89170-0C590 is fitted in these vehicles: Toyota Sequoia K20 (2008-2022). You can tell whether your car is included by matching make, model and year of construction against the list.

Below are the vehicles in which this unit was fitted.

• Toyota Sequoia K20 (2008-2022)

First compare the part number on the label of the removed unit with this page. That only ensures it is the right unit. Also have the fault memory read out beforehand, because only the log 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 89170-0C410, 891700C500.

How does the repair of the 89170-0C590 work?

First have the fault memory read out and attach the log. Then disconnect the battery and only afterwards remove the control unit. Finally, create a repair order online and send in the well-packed unit.

The order is mandatory for safety reasons. Reading out comes first, disconnecting the battery second, removing the unit last.

Airbag24 checks the unit on the test bench, repairs defective components, deletes stored crash data and carries out a function test. 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 89170-0C590 get to Airbag24?

You send the control unit 89170-0C590 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

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