Airbag control unit with part number 89170-BZ850

What does the airbag control unit 89170-BZ850 do?

The airbag control unit 89170-BZ850 controls the restraint system (SRS) of Toyota. It processes the measured values of the crash sensors and decides in an accident, within milliseconds, which airbags and seatbelt pretensioners are triggered.

The unit also checks the system continuously. It indicates faults via the airbag warning light in the instrument cluster, so that a fault becomes visible.

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

Why does the control unit 89170-BZ850 fail?

The most common cause is that crash data from an accident remains stored in the unit, even if no airbag was triggered. A normal diagnostic tool cannot erase it. Other causes that come into question are aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The electronics in the unit age like any electronics, and solder joints can go cold over time. Moisture and corrosion mainly attack the plug connections.

Voltage spikes, for example from a weak battery or a jump start, can also damage the control unit. The inspection at Airbag24 determines which cause is present.

How can you tell that the 89170-BZ850 is defective?

The airbag warning light in the instrument cluster indicates a defect. If it stays on constantly or intermittently, that is a clear sign, together with error messages in the instrument cluster, a diagnostic tool without a connection, and a fault memory that cannot be cleared.

An error message in the instrument cluster may also be displayed. If the diagnostic tool cannot connect to the control unit, or the fault memory cannot be cleared, this also points to a problem.

In such a state, airbags and seatbelt pretensioners may possibly fail to trigger in an emergency. Have the system checked promptly while the warning light is on.

Which vehicles is the 89170-BZ850 fitted in?

The control unit 89170-BZ850 is fitted in these vehicles: Toyota Avanza F650 Facelift (2015-2023).

The vehicles at a glance:

• Toyota Avanza F650 Facelift (2015-2023)

Comparing the part number on the label with this page only confirms that it is the right unit.

Also have the fault memory read out beforehand. Only the result shows whether the control unit itself is defective or whether a plug or a cable is behind it.

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-BZ850 work?

First have the fault memory read out and attach the log. Then disconnect the battery and only then remove the control unit; afterwards create a repair order online and send in the well-packed unit.

Airbag24 checks the unit on the test bench, repairs or replaces defective components, erases the stored crash data and carries out a function test. Afterwards your own unit comes back to you.

Processing at Airbag24 usually takes 3–4 working days. 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-BZ850 get to Airbag24?

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

Enclose the printed repair order in the parcel and pack the unit shock-proof.