Airbag control unit with part number 89170-BZ490

What does the airbag control unit 89170-BZ490 do?

The 89170-BZ490 is the central control unit of the restraint system (SRS) in Toyota. It processes the readings from the crash sensors and, in an accident, triggers the appropriate airbags and seatbelt pretensioners within milliseconds. At the same time it monitors the system and shows faults via the airbag warning light.

In everyday use the control unit works unnoticed in the background and only stands out when it reports a fault.

If an accident occurs, it stores crash data and then locks itself.

Why does the control unit 89170-BZ490 fail?

The most common cause is crash data stored from an earlier event in which no airbag necessarily fired. An ordinary diagnostic tool does not erase them, but Airbag24 removes them during the repair of the 89170-BZ490.

An event with crash data does not necessarily lead to a triggered airbag. The unit records the event anyway, and the data remain stored in the device.

Aged electronic components, cold solder joints, and moisture and corrosion at the plug connectors are also possible causes. Voltage spikes, for example from a weak battery or a jump start, can also damage the unit.

Whether one of these causes applies to your unit can only be established by testing on the test bench.

How can you tell that the 89170-BZ490 is defective?

A defect can show up as an airbag warning light in the instrument cluster that stays on permanently or intermittently, as an error message in the instrument cluster, as a lost connection to the diagnostic tool, or as a fault memory that cannot be cleared. In that case, airbags and seatbelt pretensioners may not be able to deploy in an emergency.

Typical signs at a glance:

• The warning light in the instrument cluster stays on permanently or keeps coming back on.
• An error message for the airbag system appears.
• The diagnostic tool cannot reach the control unit.
• The fault memory cannot be cleared despite an attempt to erase it.

Please take such signs seriously. A light that only comes on at times is just as much a signal as one that burns constantly.

Which vehicles is the 89170-BZ490 fitted in?

The 89170-BZ490 is fitted in these vehicles: Toyota Avanza F650 Facelift (2015-2023).

The vehicles for which we keep this part number on record are listed here.

• Toyota Avanza F650 Facelift (2015-2023)

Before you remove the control unit, have the fault memory read out. That way it can be shown that the control unit itself is the cause and not a plug or a cable. Then compare the part number on the label with the information on this page.

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-BZ490 work?

You read out the fault memory in advance, disconnect the battery and remove the control unit. Then you create a repair order online. At Airbag24, processing the 89170-BZ490 usually takes 3–4 working days.

The fault memory is read out first, and the log comes with the unit. After that you disconnect the battery, remove the control unit and send it in well packed.

There, the unit is checked on the test bench, defective components are replaced, the stored crash data are erased and a function test is carried out. Your own unit is then returned to you. The stated time covers only this work.

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-BZ490 get to Airbag24?

You send the control unit 89170-BZ490 to us as a parcel, or you book a UPS collection for an extra charge. The return after the repair is made by UPS.

Enclose the printed repair order with the parcel, and pack the unit so that it is shockproof.