Airbag control unit with part number 89170-BZ840

What does the airbag control unit 89170-BZ840 do?

The airbag control unit 89170-BZ840 controls the restraint system (SRS) in the Toyota. It evaluates the crash sensors, decides in an accident within milliseconds on triggering airbags and seatbelt pretensioners, and monitors the system constantly.

Faults are reported via the airbag warning light in the instrument cluster, which you should keep an eye on. This keeps the state of the system traceable at all times.

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

Why does the control unit 89170-BZ840 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery or a jump start.

An ordinary diagnostic tool cannot clear crash data. This explains why a fault persists after an accident.

Ageing components and connections depend on time and on the environment in which the unit operates. Moisture and corrosion attack the contacts, and voltage spikes put additional strain on the electronics.

Airbag24 clears the crash data during the repair.

How can you tell that the 89170-BZ840 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently. In addition an error message appears in the instrument cluster, the diagnostic tool finds no connection to the control unit, and the fault memory cannot be cleared.

In an emergency, airbags and seatbelt pretensioners may then fail to deploy. That is the reason not to ignore the indicator.

Have the vehicle checked promptly at a workshop.

Which vehicles is the 89170-BZ840 fitted in?

The 89170-BZ840 is fitted in these vehicles: Toyota Avanza F650 Facelift (2015-2023).

The list shows which vehicles are recorded for this part number.

• Toyota Avanza F650 Facelift (2015-2023)

(a) Check whether the number on the label of the removed unit matches this page. This tells you that you have the correct unit in front of you. (b) Have the fault memory read out beforehand, because only the result 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 17952812-928112, 17952815-928143, 89170-BZ440.

How does the repair of the 89170-BZ840 work?

First have the fault memory read out and enclose the log. Then disconnect the battery, only then remove the control unit, and create the repair order online. At Airbag24, checking, repairing and the function test usually take 3–4 working days.

This sequence is part of safety and must be strictly followed. Pack the unit well before you send it in.

Airbag24 checks the unit on the test bench, replaces defective components, clears stored crash data and carries out a function test. Your own unit then goes back 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-BZ840 get to Airbag24?

You send the control unit 89170-BZ840 as a parcel, or book a UPS collection for an extra charge. Airbag24 returns it to you by UPS after the repair.

Enclose the printed repair order and pack the unit shock-resistant.