Airbag control unit with part number 89170-BZ820

What does the airbag control unit 89170-BZ820 do?

The airbag control unit 89170-BZ820 is the central control unit of the restraint system (SRS) for Toyota. It evaluates the crash sensors and decides within milliseconds in the event of an accident which airbags and seatbelt pretensioners are triggered.

During operation the device checks the system. If it finds a fault, it shows this via the airbag warning light in the instrument cluster.

After an accident the control unit stores crash data and locks itself. Only the repair lifts the lock.

Why does the control unit 89170-BZ820 fail?

Stored crash data is the most common cause on the 89170-BZ820, even if no airbag has deployed. Other causes are aged components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The crash data stays in memory until it is erased, and a normal diagnostic tool does not remove it.

The remaining causes lie in the electronics. Components age, solder joints can become defective, and moisture with corrosion affects the plug contacts. Voltage spikes, for example from a weak battery or when a jump start is connected, also stress the circuit.

How can you tell that the 89170-BZ820 is defective?

The airbag warning light comes on at the 89170-BZ820 permanently or intermittently. In addition, a fault message appears in the instrument cluster, the diagnostic tool gets no connection, and the fault memory cannot be cleared. Airbags and seatbelt pretensioners may then fail to deploy in an emergency.

The warning light is the clearest indication here, because the system controls it itself. If it stays on permanently, there is a fault in the system that must be checked.

A missing connection to the diagnostic tool can also have other causes, such as a cable or a plug. Only the fault memory shows which one it is.

Which vehicles is the 89170-BZ820 fitted in?

The 89170-BZ820 is fitted in these vehicles: Toyota Avanza F650 Facelift (2015-2023).

For orientation, the list of vehicles stored for this part number follows.

• Toyota Avanza F650 Facelift (2015-2023)

Compare the part number on the label of the removed device with this page. This only checks whether it is the right device. Also have the fault memory read out beforehand, because 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 17952812-928112, 17952815-928143, 89170-BZ440.

How does the repair of the 89170-BZ820 work?

First you read out the fault memory and attach the log. Then you disconnect the battery, remove the 89170-BZ820 and create a repair order online. You send the well packed device in; Airbag24 checks, repairs and tests it before it is returned.

The order is mandatory for safety reasons, because the restraint system must not be triggered unintentionally during the work.

Processing at Airbag24 usually takes 3–4 working days. This time applies only to checking, repairing and testing.

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-BZ820 get to Airbag24?

You send the 89170-BZ820 in as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 returns the device by UPS.

Put the printed repair order into the parcel and pack the device shockproof.