Airbag control unit with part number 89170-F4420

What does the airbag control unit 89170-F4420 do?

The airbag control unit 89170-F4420 is the central control unit of the restraint system (SRS) for Toyota. It evaluates the crash sensors, decides within milliseconds in a crash which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. It indicates faults via the airbag warning light.

Monitoring covers sensors, trigger circuits and the wiring between the components. Deviations are recorded in the fault memory.

After a crash the control unit stores crash data and locks itself.

Why does the control unit 89170-F4420 fail?

The most common cause is crash data from an earlier accident, even if no airbag was triggered. Other causes are aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes from a weak battery or a jump start.

Crash data stays in the unit until the repair removes it. A standard diagnostic tool cannot erase it.

Aged components and plug connections can act together: a contact that sometimes carries current and sometimes does not throws the control unit off balance. Moisture and corrosion on the plugs make this worse.

How can you tell that the 89170-F4420 is defective?

A defect shows up as the airbag warning light in the instrument cluster, which lights up permanently or intermittently, and as a fault message in the instrument cluster. In addition, no connection to the diagnostic tool is established, and the fault memory cannot be cleared.

With these signs, airbags and seatbelt pretensioners may not trigger in a crash. The warning light is therefore the first hint you should follow up.

Which vehicles is the 89170-F4420 fitted in?

The airbag control unit 89170-F4420 is fitted in these vehicles: Toyota C-HR NGX10 Facelift (2019-2023).

The list below shows the vehicles for which this part number is recorded.

• Toyota C-HR NGX10 Facelift (2019-2023)

Compare the part number on the label of the removed unit with this page. That only confirms that it is the right unit. Have the fault memory read out before you remove the control unit, since that 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-F4210, 8917010110.

How does the repair of the 89170-F4420 work?

First have the fault memory read out and attach the log. Then disconnect the battery and only then remove the control unit. The processing time at Airbag24 is usually 3–4 working days.

Online you create the repair order and send in the well-packed unit. Airbag24 checks it, replaces defective components, erases stored crash data and carries out a function test. Afterwards the unit is returned 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-F4420 get to Airbag24?

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

Place the printed repair order in the parcel. Pack the unit shock-proof.