Airbag control unit with part number 89170-42C90

What does the airbag control unit 89170-42C90 do?

The airbag control unit 89170-42C90 controls the restraint system (SRS) of Toyota: it records the readings from the crash sensors, decides within milliseconds whether airbags and seatbelt pretensioners are to be triggered in an emergency, and monitors the system. It reports faults via the airbag warning light, and after an accident it stores crash data and locks itself.

Monitoring runs regardless of whether you are currently driving. In everyday use, the unit is therefore only noticeable when something is wrong.

Why does the control unit 89170-42C90 fail?

The most common cause is stored crash data after an accident, even if no airbag was triggered. Other possible causes include ageing components, cold solder joints, moisture, corrosion and voltage spikes.

Crash data remains in the memory after an accident, and a normal diagnostic tool does not erase it. Airbag24 removes it as part of the repair.

Further causes in detail:

• aged electronic components
• cold solder joints
• moisture and corrosion at plug connections
• voltage spikes, for example from a weak battery

How can you tell that the 89170-42C90 is defective?

A fault shows up as the airbag warning light staying on permanently or intermittently, as an error message in the instrument cluster, as a diagnostic tool that cannot connect to the control unit, or as a fault memory that cannot be cleared.

If you notice any of these signs, it is a clear signal to have the unit checked. Until then, airbags and seatbelt pretensioners may not be able to trigger in an emergency.

Which vehicles is the 89170-42C90 fitted in?

The control unit 89170-42C90 is fitted in these vehicles: Toyota RAV4 XA50 (from 2018). To compare it with your car, it is most sensible to check the vehicle documents.

The vehicles as a list:

• Toyota RAV4 XA50 (from 2018)

The label comparison confirms that the removed unit matches this page, but it does not do more than that. Also have the fault memory read out. 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 89170-42C90 work?

First have the fault memory read out and attach the log. Then disconnect the battery and remove the control unit. After that, create a repair order online and send the unit well packed. Airbag24 tests it on the test bench, repairs defective components, deletes the crash data and carries out a function test.

Processing at Airbag24 usually takes 3–4 working days. You then receive your own, repaired unit back.

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 89170-42C90 get to Airbag24?

You either send the unit as a parcel, or you book a UPS collection for an extra charge. The return after repair is also made by UPS.

Enclose the printed repair order with the parcel, and the unit must be packed shockproof.