Airbag control unit with part number 89170-48A40

What does the airbag control unit 89170-48A40 do?

The airbag control unit 89170-48A40 manages the restraint system (SRS) of Lexus. It checks the crash sensors and decides in an accident, within milliseconds, which airbags and seatbelt pretensioners are triggered.

During operation it monitors all components and shows faults via the airbag warning light.

After an accident, it writes crash data and remains locked afterwards.

Why does the control unit 89170-48A40 fail?

The most common cause with the 89170-48A40 lies in crash data that was stored after an accident, even without an airbag triggering. Ageing electronics, cold solder joints, moisture and corrosion, and voltage spikes also come into play.

A standard diagnostic tool does not remove this data.

The other causes act gradually. Solder joints go cold, components age, and moisture attacks the contacts. Voltage spikes, for example from a weak battery, additionally stress the electronics.

How can you tell that the 89170-48A40 is defective?

A defect in the 89170-48A40 can be recognised by the airbag warning light, which lights up permanently or intermittently. Error messages, a missing connection to the diagnostic tool and a fault memory you cannot clear also appear.

The warning light in the instrument cluster is the clearest indication of a fault. An accompanying error message shows that the system has detected the fault.

In an emergency, airbags and seatbelt pretensioners may then fail to trigger. Therefore have the system checked if you notice anything.

Which vehicles is the 89170-48A40 fitted in?

The 89170-48A40 is fitted in these vehicles: Lexus RX AL20 (2015-2019). Compare the part number on the removed unit with this page beforehand.

Here you see the assigned vehicles:

• Lexus RX AL20 (2015-2019)

The label comparison confirms that you have the right unit in front of you, nothing more. Only a fault memory read out beforehand 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 89170-0E021, 89170-48210, 89170-48211, 891700000000000016768827392, 89170000000000005112856576.

How does the repair of the 89170-48A40 work?

The fault memory is read out first, and you enclose the log. Then you disconnect the battery and only then remove the control unit 89170-48A40. Afterwards create the repair order online and send the unit in; processing at Airbag24 usually takes 3–4 working days.

This sequence is important, because the restraint system can only be safely handled once the battery is disconnected.

Airbag24 then examines the unit on the test bench, replaces defective components, deletes crash data and carries out a function test. Your own unit goes back afterwards. 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 89170-48A40 get to Airbag24?

There are two shipping options: the parcel, or a UPS collection for an extra charge. After the repair, Airbag24 sends the control unit 89170-48A40 back by UPS.

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