Airbag control unit with part number 89170-F4020

What does the airbag control unit 89170-F4020 do?

The airbag control unit 89170-F4020 controls the restraint system (SRS) in vehicles of Toyota. It evaluates the crash sensors and decides within milliseconds in an accident which airbags and seatbelt pretensioners are triggered.

Outside an accident it checks the system continuously. If it detects a fault, it reports it via the airbag warning light.

After an accident it stores crash data and locks itself.

Why does the control unit 89170-F4020 fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered; a normal diagnostic tool cannot erase it. Other causes are aging electronic components, cold solder joints, moisture and corrosion at plugs, and voltage spikes from a weak battery or a jump start.

Crash data therefore stays in the unit even when nothing visibly damaged is found on the airbags. Airbag24 erases it during the repair.

The other causes concern electronics and connections. Components age, solder joints can be cold, and moisture and corrosion affect plug connections. Voltage spikes can act alone or together with these factors.

How can you tell that the 89170-F4020 is defective?

A defect in the 89170-F4020 can be recognised by several signs: the warning light stays lit permanently or intermittently, a message appears on the instrument cluster display, the diagnostic tool cannot reach the control unit, and the fault memory remains. In an emergency, airbags and seatbelt pretensioners may then not trigger.

The airbag warning light in the instrument cluster is usually the first thing to notice. It comes on as soon as the control unit detects a fault in the restraint system, which makes it a reliable indicator.

Have the fault memory read out as soon as the light comes on, even if it goes out again afterwards.

Which vehicles is the 89170-F4020 fitted in?

The 89170-F4020 is fitted in these vehicles: Toyota C-HR NGX10 (2017-2019).

This overview shows which vehicles have so far been recorded for this part number:

• Toyota C-HR NGX10 (2017-2019)

Compare the part number on the label of the removed unit with this page. This only clarifies whether it is the right unit. Also have the fault memory read out, because it shows whether the control unit is defective or whether a plug or a 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-F4020 work?

The 89170-F4020 is removed only after the fault memory has been read out, the log has been enclosed and the battery has been disconnected. Afterwards you create a repair order online and send the unit in. Testing, repair and function testing at Airbag24 take 3–4 working days as a rule.

The order of steps is mandatory for safety reasons. At Airbag24 the unit is examined on the test bench, defective components are replaced, crash data is erased and a function test follows. Afterwards your own, repaired 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-F4020 get to Airbag24?

You send the control unit 89170-F4020 as a package yourself, or you book a UPS collection for an extra charge. After the repair, Airbag24 returns the unit to you via UPS.

Include the printed repair order in the package, and protect the unit with a shock-resistant box.