Airbag control unit with part number 89170-52A40

What does the airbag control unit 89170-52A40 do?

The airbag control unit 89170-52A40 is the central control unit of the restraint system (SRS) for Toyota. It processes the crash sensor signals and decides in an accident, within milliseconds, which airbags and seatbelt pretensioners are triggered.

It also monitors the entire system and reports faults via the airbag warning light in the instrument cluster.

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

Why does the control unit 89170-52A40 fail?

Stored crash data is the most common cause when the control unit 89170-52A40 fails, even if no airbag has deployed. A normal diagnostic tool cannot erase it. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

Crash data remains in the memory after an accident, regardless of whether an airbag deployed. Ageing electronic components and cold solder joints can affect the unit over time.

Moisture and corrosion at plug connectors, as well as voltage spikes, for example from a weak battery or a jump start, are also possible causes. Only the inspection shows which cause applies to your unit.

How can you tell that the 89170-52A40 is defective?

The airbag warning light in the instrument cluster stays on permanently or only intermittently, and a fault message appears in the instrument cluster. Added to this are a failed connection from the diagnostic tool and a fault memory that cannot be cleared.

Typical signs at a glance:

• Airbag warning light stays on permanently or intermittently
• Fault message in the instrument cluster
• Diagnostic tool cannot establish a connection to the control unit
• Fault memory cannot be cleared

In an emergency, airbags and seatbelt pretensioners may fail to deploy. Please have the warning checked promptly.

Which vehicles is the 89170-52A40 fitted in?

The control unit 89170-52A40 is fitted in these vehicles: Toyota Yaris XP90 (2005-2009) and XP90 Facelift (2009-2011).

The vehicles for this part number are listed here:

• Toyota Yaris XP90 (2005-2009)
• Toyota Yaris XP90 Facelift (2009-2011)

Compare the part number on the label of the removed unit with this page. This only confirms that you have the correct unit. Have the fault memory read out beforehand, because only it shows whether the control unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 212986-105, 212986-110, 220749-101, 89170-0D170, 89170-0D230, 89170-0D440.

How does the repair of the 89170-52A40 work?

First have the fault memory read out and enclose the log. Then disconnect the battery and only then remove the control unit 89170-52A40. Processing at Airbag24 usually takes 3–4 working days.

You then create a repair order online and send in the unit, well packed. Airbag24 checks it on the test bench, replaces defective components, erases the 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 89170-52A40 get to Airbag24?

You send the control unit 89170-52A40 as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Place the printed repair order in the parcel and pack the unit shock-resistant.