Airbag control unit with part number 89170-48C20

What does the airbag control unit 89170-48C20 do?

The airbag control unit 89170-48C20 is the central control unit of the restraint system (SRS) of Lexus. It checks the crash sensors, decides in an accident within milliseconds whether airbags and seatbelt pretensioners are triggered, and monitors the system continuously. After an accident it stores crash data and locks itself.

The system comprises several sensors, cables and actuators, and the control unit keeps all of them in view. If it detects a fault, the airbag warning light in the instrument cluster comes on.

Because the system must work without delay in an emergency, every warning is a reason to find the cause.

Why does the control unit 89170-48C20 fail?

Stored crash data is the most common cause, even if no airbag has deployed. A normal diagnostic tool cannot delete it. Other causes include aged electronic components, cold solder joints, moisture and corrosion at plug connectors, and voltage spikes.

The data arises in an accident and remains in the unit, even if the vehicle could continue unremarkably afterwards.

Components age, solder joints on the circuit board can become cold, and moisture with corrosion impairs the contacts at the plug connectors.

Voltage spikes in the vehicle electrical system, for example from a weak battery or a jump start, additionally stress the electronics.

How can you tell that the 89170-48C20 is defective?

A defect shows itself through the airbag warning light in the instrument cluster, which lights up permanently or intermittently, through an error message there, and through a diagnostic tool that cannot connect to the control unit. A fault memory that cannot be cleared is a further sign. In an emergency, airbags and seatbelt pretensioners may then possibly not trigger.

These signs belong together and can only be classified together. A light without any noticeable change in driving does not mean that everything is in order.

Which vehicles is the 89170-48C20 fitted in?

The control unit 89170-48C20 is fitted in these vehicles: Lexus RX AL20 Facelift (2019-2022) and AL20 (2015-2019). The assignment helps classify the part number, nothing more.

The list for the part number looks like this:

• Lexus RX AL20 Facelift (2019-2022)
• Lexus RX AL20 (2015-2019)

Compare the part number on the label of the removed unit with this page in advance, so you can see that it is the right unit. Also read out the fault memory before you remove anything, because only that 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, 89170-0E260, 89170-48490, 89170-48890, 89170-48A00, 89170-48A10.

How does the repair of the 89170-48C20 work?

First have the fault memory read out and attach the log, then disconnect the battery and only then remove the control unit. Then create a repair order online and send in the well-packed unit. At Airbag24, testing, repair and function test take 3–4 working days as a rule.

At Airbag24 the unit is inspected on the test bench, defective components are repaired, stored crash data is deleted and a function test is carried out. Afterwards your own unit returns 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 89170-48C20 get to Airbag24?

You can send the unit as a parcel or book a UPS collection for an extra charge. After the repair Airbag24 returns it by UPS.

The printed repair order goes into the parcel, and the control unit should be packed shock-resistant.