Airbag control unit with part number 89170-F4170

What does the airbag control unit 89170-F4170 do?

The airbag control unit 89170-F4170 is the central control unit of the restraint system (SRS) for Toyota. It evaluates the signals from the sensors, decides in an accident within a few milliseconds which airbags and seatbelt pretensioners are triggered, and monitors the entire system continuously.

If the control unit detects a fault, it enters it in the fault memory and reports it via the airbag warning light in the instrument cluster. This monitoring runs in the background throughout the entire journey, without you having to trigger anything.

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

Why does the control unit 89170-F4170 fail?

Most common cause is crash data stored after an accident, even if no airbag has triggered; a normal diagnostic tool cannot delete it. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes in the vehicle electrical system.

Crash data is the record that the control unit secures after an impact. It remains in the unit until it is removed, and that is exactly what happens at Airbag24 during the repair. After that the control unit can be read out again.

The other causes also occur without an accident. Electronic components age, solder joints can be poorly connected, and moisture promotes corrosion at the contacts. Voltage spikes, for example from a weak battery or jump-starting, additionally stress the electronics.

How can you tell that the 89170-F4170 is defective?

A defect shows itself through the airbag warning light in the instrument cluster, which lights up permanently or intermittently, and through an error message in the instrument cluster. Add to this a diagnostic tool without connection to the control unit and a fault memory that cannot be cleared.

• The airbag warning light in the instrument cluster lights up permanently or intermittently.
• An error message about the airbag system appears in the instrument cluster.
• The diagnostic tool has no connection to the control unit.
• The fault memory cannot be cleared.

If one of these signs is present, airbags and seatbelt pretensioners may not trigger in an emergency. Please have such a warning signal clarified promptly and do not postpone the check.

Which vehicles is the 89170-F4170 fitted in?

The airbag control unit 89170-F4170 is fitted in these vehicles: Toyota C-HR NGX10 (2017-2019).

You can see the allocation to this part number here:

• Toyota C-HR NGX10 (2017-2019)

Two steps will help you. First compare the part number on the label of the removed unit with this page, so that you know it is the correct unit. Also have the fault memory read out beforehand, because only this result 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 89170-F4210, 8917010110.

How does the repair of the 89170-F4170 work?

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

At Airbag24 the unit is first examined on the test bench. Defective components are repaired, stored crash data is deleted and a function test is carried out. Afterwards your own, repaired unit is returned to you.

The 3–4 working days apply solely to checking, repairing and testing at Airbag24 and not to your steps or the shipping. 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-F4170 get to Airbag24?

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

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