Airbag control unit with part number 89170-53640

What does the airbag control unit 89170-53640 do?

The 89170-53640 is the central control unit of the restraint system (SRS) in Lexus. It checks the crash sensors, decides within milliseconds in a crash which airbags and seatbelt pretensioners are triggered, and monitors the system continuously. Faults are shown via the airbag warning light.

The evaluation happens without any action from the driver, because the system must react without delay in an emergency.

After a crash, the control unit stores crash data and locks itself. This is why it is more than a switching point: it is also a data store of the accident.

Why does the control unit 89170-53640 fail?

The most common cause is stored crash data from an accident, even if no airbag has deployed; a standard diagnostic tool cannot erase it. Other causes include aged electronics, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

Airbag24 erases the crash data as part of the repair, so you do not need to take care of it.

Voltage spikes, for example from a weak battery or a jump start, can stress components. Solder joints and plug connections are sensitive to moisture and corrosion.

Which component is affected is shown only by the check on the test bench.

How can you tell that the 89170-53640 is defective?

A fault shows when the airbag warning light in the instrument cluster lights up permanently or intermittently, an error message appears, or the diagnostic tool cannot get a connection to the control unit. In addition, there is a fault memory that cannot be cleared; then airbags and seatbelt pretensioners may not deploy in an emergency.

Above all, the warning light in the instrument cluster is a clear signal, because it directly shows that the system has detected a fault.

A fault memory that cannot be cleared indicates that the fault is stored in the system and should be checked.

Which vehicles is the 89170-53640 fitted in?

The 89170-53640 is fitted in these vehicles: Lexus IS XE30 Facelift (2016-2020) and XE30 (2013-2016). What counts is the part number, not the model designation alone.

The list of vehicles for this part number is found here:

• Lexus IS XE30 Facelift (2016-2020)
• Lexus IS XE30 (2013-2016)

You should compare the part number on the label of the removed unit with this page. The comparison only confirms that it is the correct unit. Also have the fault memory read out before removal, because only this result shows whether the control unit is defective or whether a connector or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 89170-53250, 89170-53370, 89170-53700.

How does the repair of the 89170-53640 work?

First have the fault memory read out and enclose the log, then disconnect the battery before you remove the control unit. Afterwards you create a repair order online and send in the unit, well packed. At Airbag24, testing, repairing and function testing usually take 3–4 working days, during which defective components are replaced and the crash data is erased.

The sequence must be observed for safety reasons, especially when disconnecting the battery.

After the function test, your own unit is returned 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 89170-53640 get to Airbag24?

You can send the control unit 89170-53640 as a parcel, or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back to you by UPS.

Enclose the printed repair order in the parcel, and the unit must be packed shockproof.