Airbag control unit with part number 89170-24120

What does the airbag control unit 89170-24120 do?

The airbag control unit 89170-24120 controls the restraint system (SRS) in Lexus. It processes the measured values from the crash sensors and decides in an accident, within a fraction of a second, which airbags and seatbelt pretensioners fire.

Outside an accident the unit checks without interruption whether all components of the system are working. It keeps any faults it finds in the fault memory and displays them via the airbag warning light in the instrument cluster.

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

Why does the control unit 89170-24120 fail?

The most common cause is crash data stored after an accident, even if no airbag fired. In addition there are aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes, such as those from a weak battery or from starting with external power.

A standard diagnostic tool cannot remove the crash data. Airbag24 erases it during the repair, so the unit works without this entry afterwards.

Components that age lose their reliability over the years. Cold solder joints sometimes make contact only intermittently, which makes faults hard to reproduce.

Moisture and corrosion attack the contacts in the plug connectors. High voltage spikes, for example from a weak battery or from starting with external power, put additional strain on the electronics.

How can you tell that the 89170-24120 is defective?

A defect shows up as the airbag warning light in the instrument cluster, which stays on permanently or intermittently. Fault messages may also appear in the instrument cluster, the diagnostic tool may find no connection to the control unit, or the fault memory cannot be cleared.

Watch for these signs, because in the event of a fault the airbags and seatbelt pretensioners may fail to deploy in an emergency.

If you see such a finding, have the system examined promptly rather than waiting.

Which vehicles is the 89170-24120 fitted in?

The 89170-24120 is fitted in these vehicles: Lexus RC ASC10 (2015-2018) and ASC10 Facelift (from 2018).

The list assigns the vehicles that are recorded with this part number:

• Lexus RC ASC10 (2015-2018)
• Lexus RC ASC10 Facelift (from 2018)

The comparison of the part number on the label with this page only confirms that you have the matching unit. Nothing more is proven by this comparison.

Have the fault memory read out before removing the unit. Only this result shows whether the control unit is defective or whether a plug or a cable is causing the fault.

For the same vehicles, we also repair control units with the part numbers 89170-24170, 89170-24300, 89170-24320, 89170-24340, 89170-78010.

How does the repair of the 89170-24120 work?

First have the fault memory read out and enclose the log, then disconnect the battery before you remove the control unit. Next, create a repair order online and send in the well-packed unit.

Processing at Airbag24 usually takes 3–4 working days for checking, repairing and testing. The unit is examined on the test bench, and defective components are replaced.

Airbag24 then erases the stored crash data and carries out a function test. After that your own unit 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 89170-24120 get to Airbag24?

You send the control unit 89170-24120 as a parcel or, for an extra charge, book a UPS collection. After the repair, Airbag24 sends it to you by UPS.

Pack the control unit shock-proof and put the printed repair order in the parcel.