Airbag control unit with part number 89170-78030

What does the airbag control unit 89170-78030 do?

The airbag control unit 89170-78030 controls the restraint system (SRS) of Lexus. It evaluates the crash sensors, decides in an accident within milliseconds whether to trigger airbags and seatbelt pretensioners, and monitors the system continuously.

The unit detects faults itself and shows them via the airbag warning light in the instrument cluster. This keeps it visible whether the system is working properly.

After an accident the control unit stores crash data and locks itself. This state is a fixed part of the system logic.

Why does the control unit 89170-78030 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; a normal diagnostic tool cannot erase it. Other causes are ageing components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The crash data stays in the unit, because an ordinary diagnostic tool has no access to remove it. As a result, the failure cannot be clarified by erasing alone.

Electronic components age, and over time solder joints can go cold. Contact at plug connections suffers when moisture or corrosion is added.

Voltage spikes, for example from a weak battery or from jump-starting, can additionally damage the electronics.

How can you tell that the 89170-78030 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and a message appears in the display. In addition, the diagnostic tool gets no connection to the control unit, and the fault memory cannot be cleared.

The warning light is the indication you notice first. It shows that the system has detected a fault.

In an emergency, airbags and seatbelt pretensioners may not be able to deploy. Therefore do not ignore the indication and have the cause clarified.

Which vehicles is the 89170-78030 fitted in?

The 89170-78030 is fitted in these vehicles: Lexus NX AZ10 (2014-2017) and AZ10 Facelift (2017-2021).

The vehicles from the stored data are listed here:

• Lexus NX AZ10 (2014-2017)
• Lexus NX AZ10 Facelift (2017-2021)

Compare the part number on the label of the removed unit with this page. This only ensures that you have the right unit in front of you. Also have the fault memory read out beforehand, because only the result 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 89170-78010.

How does the repair of the 89170-78030 work?

First read out the fault memory and enclose the log, then disconnect the battery and remove the control unit. Then create a repair order online and send the unit in well packed. Airbag24 checks, repairs and tests it as a rule within 3–4 working days.

The order is for safety: the unit is only removed once the battery is disconnected.

At Airbag24 the unit is examined on the test bench, defective components are replaced and stored crash data is erased. A function test concludes the work, after which your own unit goes back.

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 89170-78030 get to Airbag24?

You send the unit in a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 sends it back by UPS.

Place the printed repair order in the parcel. Pack the control unit shockproof.